Invitation to help writing and submitting papers -- how does this scam work? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. { Risky business. I wrote a function that reads the first byte of the eeprom. Would it be possible for a civilization to create machines before wheels? How much space did the 68000 registers take up? Because of this, the incoming coordinates are stored as Strings. hi im kinda new to arduino but i was task todo this project where i have to interface arduino una + sd card +rfid + rtc . . (Ep. Is a dropper post a good solution for sharing a bike between two riders? Does, No, I want arrTeamMembers to contain "Michael | Steve | Thomas | Jeff | Susan | Helen |", If you want the first item to be the value of. 9. how to change a const char* - Arduino Stack Exchange #define DHTPIN D4 // what digital pin we're connected to#define DHTTYPE DHT11 // select dht type as DHT 11 or DHT22DHT dht(DHTPIN, DHTTYPE); void setup() { Serial.begin(9600); delay(1000); WiFi.begin(WIFI_SSID, WIFI_PASSWORD); //try to connect with wifi Serial.print("Connecting to "); Serial.print(WIFI_SSID); while (WiFi.status() != WL_CONNECTED) { Serial.print(". c++ - Cannot convert string to const char - Stack Overflow Cannot convert 'std::string' to 'const char* - Stack Overflow You can get two birds with one stone here though. That's what you should provide: char ssid [] = "YOUR_SSID"; // this is changed const char* password = "YOUR_PASSWORD"; // this is fine [.] That makes them non-const so the error message should go away. Making statements based on opinion; back them up with references or personal experience. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. Learn more about Stack Overflow the company, and our products. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. Depending on what you are actually trying to do, you might want this: The problem is, arrTeamMembers is an array of strings, while tb.Text is simply a string. That worked great. Is it really in the format of your first string? Additional benefit is both this methods are constant with respect to complexity as opposed to the linear complexity of strlen, If you REALLY want to use strlen use s.c_str(): strlen(s.c_str()). The compiler is not giving me the error anymore since i'm using this writing : I still have to figure out if it totally work, I'll check. In the code I attached what I am trying to do is to save the "String password = "1234567890"; to EEPROM and than reading it from EEPROM.And after reading it from EEPROM I am converting it into "const char* pass2". String inString = ""; // string to hold input void setup() { // Open serial communications and wait for port to open: Serial.begin(9600); while (!Serial) { ; // wait for serial port to connect. Sonoff Basic R2 unresponsive after upgrade, Lolin D1 Mini V4 problems with analog input reading, Speed up connection to WiFi after power on reset, NodeMCU: Failed uploading: uploading error: exit status 2, How to Set an ESP8266 NodeMCU Access Point for a Web Server, Build a Water Level Control System Using ESP8266 NodeMCU. What would stop a large spaceship from looking like a flying brick? When are complicated trig functions used? raul81 August 4, 2015, 6:56am Only convert string to C strings when calling C functions for which there is not a C++ alternative. Error: Morse theory on outer space via the lengths of finitely many conjugacy classes, Non-definability of graph 3-colorability in first-order logic, Identifying large-ish wires in junction box, Book set in a near-future climate dystopia in which adults have been banished to deserts. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Why on earth are people paying for digital real estate? How much space did the 68000 registers take up? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. temp_string=bluetooth_Buffer.substring(9,13); What does this mean?: cannot convert 'const char [28]' to - Reddit Soo that's why I'm here. { How does the inclusion of stochastic volatility in option pricing models impact the valuation of exotic options? string[] arrTeamMembers = new string[] { tb.Text }; worked !! Arduino toCharArray () String char 2 1 1 void loop(){ String stringOne = "A string"; char Buf[50]; stringOne.toCharArray(Buf, 50) } stringOne String Buf char 50 By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Thank you for you time in advance. Connect and share knowledge within a single location that is structured and easy to search. I've had experiences where something. Not the answer you're looking for? I dont know what is the problem with my code void newthings(String s) Just a general hint - if something goes wrong with standard functions, 99.99% of the time it's your fault. I am creating a dynamic array, and getting an error: Error message: Cannot convert type 'string' to 'string[]', tb.Text contains values such as "Michael | Steve | Thomas | Jeff | Susan | Helen |". @user1575615 C++ "reimplements" many of the C features (e.g., using class, Why on earth are people paying for digital real estate? Thanks. -1 I want to get this code to recognise different commands and be able to parse the rest of the command, fore example I send "/sleep 5", and it will sleep for 5 seconds. Not the answer you're looking for? Which is valid until the next call to a non-const member of string (or the destructor of the string object). Find centralized, trusted content and collaborate around the technologies you use most. Is there a deep meaning to the fact that the particle, in a literary context, can be used in place of , Cultural identity in an Multi-cultural empire. By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. How does the inclusion of stochastic volatility in option pricing models impact the valuation of exotic options? First of all, you need to convert the other data type into String using the append operator; then, you can use the above method to convert this String into char. Powered by Discourse, best viewed with JavaScript enabled, cannot convert 'String' to 'char*' for argument '1' to 'int sprintf(char*, const. rev2023.7.7.43526. //Processing the extra_value figures c++ - Convert string to const char* issue - Stack Overflow Morse theory on outer space via the lengths of finitely many conjugacy classes. I want to convert a string data to const unsigned char with code. Here's my code: tweet = strstr (tweet, "]"); There is no reason why you would want to . function_temp.activity = int(temp) ; Thanks for contributing an answer to Arduino Stack Exchange! Do I remove the screw keeper on a self-grounding outlet? What would stop a large spaceship from looking like a flying brick? Problem with "converting a string constant to 'char*'" in the WiFi library, Why on earth are people paying for digital real estate? float t = dht.readTemperature(); // Read temperature as Celsius (the default), if (isnan(h) || isnan(t)) { // Check if any reads failed and exit early (to try again). else if (bluetooth_Buffer[3]!=',') What are the Arduino hardware options for experimenting with IoT? Reddit, Inc. 2023. Error message: Cannot convert type 'string' to 'string[]' By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. Thanks for contributing an answer to Stack Overflow! Please add the error message to the question (click on "edit") rather than as a comment. Other than Will Riker and Deanna Troi, have we seen on-screen any commanding officers on starships who are married? 2. Depending on what you are actually trying to do, you might want this: string [] arrTeamMembers = new string [] { tb.Text }; or. The best answers are voted up and rise to the top, Not the answer you're looking for? I am trying to pass the values from tb.Text to arrTeamMembers. 1 2 3 4 5 6 7 8 9 10 11 12 - Edgar Bonet Jun 5, 2022 at 16:19 that's a warning, not an error . temp_string=bluetooth_Buffer.substring(4,8); Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. How to convert a String to a char * in Arduino? if (int(bluetooth_Buffer.length())!=13) //Hard coded dimensions and particularities of the message Has a bill ever failed a house of Congress unanimously? Asking for help, clarification, or responding to other answers. However, I keep on getting this error "cannot convert 'String' to 'const char*'". Identifying large-ish wires in junction box. Thanks for contributing an answer to Stack Overflow! Hi, im using the library pubsubclient for MQTT. gauravntpl August 16, 2017, 12:58pm 1. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. void loop(){ String stringOne = "A long integer: "; stringOne += 1234; char charBuf[50]; stringOne.toCharArray(charBuf, 50) } int n = WiFi.scanNetworks (); . Are there ethnically non-Chinese members of the CCP right now? ")); return; }. The error message tells you everything you need to know. Announcement: esp8266.com is closed; specifically,[], It takes about 20-25 seconds for home assistant c[], I tried to upgrade tof my sonoff basic R2 with the[], Hi, I'm developing a mobile IoT solution. So not all C functions can be used in C++? How can I learn wizard spells as a warlock without multiclassing? Using string::c_str function We can easily get a const char* from the std::string in constant time with the help of the string::c_str function. Hey all I am trying to convert a string into a uint8_t with the following code: cannot convert 'String' to 'uint8_t {aka unsigned char}' in initialization. It shows . bluetooth_Buffer = ""; Invitation to help writing and submitting papers -- how does this scam work? I am NOT trying to split the text. - I am not trying to split the text. I honestly don't understand why because the .substring method should give me a string which should be used by atoi, soo as far as i know there shouldn't be problem with that. Need to improve battery life of my ESP8266 Temp Hum sensor. In file included from D:\Programming\Arduino\Projects\Firebase_temperature\Firebase_temperature.ino:4: C:\Users\PRANAV\Documents\Arduino\libraries\Firebase_Arduino_Client_Library_for_ESP8266_and_ESP32\src/Firebase.h:108:30: note: initializing argument 1 of 'void Firebase_ESP_Client::begin(FirebaseConfig*, FirebaseAuth*)'. function_temp.extra_value = int(temp); critical chance, does it have any reason to exist? temp=atoi(temp_string); Can ultraproducts avoid all "factor structures"? 587), The Overflow #185: The hardest part of software is requirements, Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Testing native, sponsored banner ads on Stack Overflow (starting July 6), Converting a substring to integer with toInt, PYTHON How to convert string into int or float, Convert string to int or float *if possible*, Convert string to int, float or leave it as string, depending on the best option, Using Lin Reg parameters without Original Dataset. Someone needs to teach the OP the difference between a textual representation of an initializer list for a character array, and a C++ String instance, and a bitmap in memory (be it in RAM or PROGMEM). Can I still have hopes for an offer as a software developer. How should I select appropriate capacitors to ensure compliance with IEC/EN 61000-4-2:2009 and IEC/EN 61000-4-5:2014 standards for my device? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. String to const char* using "string.c_str ();" Using Arduino Programming Questions. Websockets with the ESP8266 using arduino uno board. Why is it doing this? Check first. If you are receiving the error "cannot convert 'String' to 'const char*" then you are trying to pass a String data type into a function that is expecting a character array. bluetooth_Buffer = ""; Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Characters with only one possible next character, Cultural identity in an Multi-cultural empire. Arduino Stack Exchange is a question and answer site for developers of open-source hardware and software that is compatible with Arduino. Problem with : cannot convert 'String' to 'const char - Arduino Forum can you guys help me . How exactly is the server giving you the binary data? Error: cannot convert 'String' to 'const char*' for argument '1' to Thanks for the help, Nick! here is my code: Spying on a smartphone remotely by the authorities: feasibility and operation. char stringTochar(String s) To learn more, see our tips on writing great answers. Asking for help, clarification, or responding to other answers. Connect and share knowledge within a single location that is structured and easy to search. Instead of strlen() (a C-style function), use string::size(): Here you have a reference with all methods from class string. When you change from String to character array (char[]) the error should go away (plus other problems you have yet to run into will never arise). WiFi.h and AT commands mix? Identifying large-ish wires in junction box. exit status 1 cannot convert 'const char [28]' to 'FirebaseConfig*' {aka 'fb_esp_cfg_t*'} This report would have more information with "Show verbose output during compilation" option enabled in File -> Preferences. In an Arduino program I'm working on the GPS sends the coordinates to the arduino through USB. Compile error - cannot convert 'String' to 'const char*', https://www.hackster.io/rayburne/warwalking-a9c021, Re: Compile error - cannot convert 'String' to 'const char*'. i need to store my rfid scan digits to a variable then try looking for that var in my given text file. Thank you for you time in advance. Depending on how the strings look, you might have to modify the format string, of course. curLongitude.toInt () ). ), Error: Cannot implicitly convert type 'string' to 'string[], Error Cannot implicitly convert type 'string[]' to 'string', Error Unable to cast object of type 'System.Int32' to type 'System.String', Cannot implicitly convert type 'string[]' to 'string', Cannot convert from 'string[]' to 'string'. Can ultraproducts avoid all "factor structures"? How should I select appropriate capacitors to ensure compliance with IEC/EN 61000-4-2:2009 and IEC/EN 61000-4-5:2014 standards for my device? Characters with only one possible next character. If you want to stick with String, use "+" instead of sprintf If you want to be sensible, ditch the String class, and use C strings. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Is there any potential negative effect of adding something to the PATH variable that is not yet installed on the system? Making statements based on opinion; back them up with references or personal experience. curLongitude.toInt()). What version of the library are you using? Asking for help, clarification, or responding to other answers. char arr[12]; The solution was char __dataFileName [sizeof (dataFileName)]; dataFileName.toCharArray (__dataFileName, sizeof (__dataFileName)); pinMode (SD_PIN,OUTPUT); dataFile = SD.open (__dataFileName,FILE_WRITE); Share Improve this answer updatenewstatus(test); This looks suspiciously like an issue of the WiFi library that was fixed five years ago. str1.data () is not guaranteed to be null terminated so I would be a bit careful of this. cannot convert 'String' to 'char*' for argument '1' to 'int sprintf What does "Splitting the throttles" mean? //Processing the activity figures String MQTT_ROOT = "/home/dg/"; const String MQTT_GetTemperature . Languages which give you access to the AST to modify during compilation? Were Patton's and/or other generals' vehicles prominently flagged with stars (and if so, why)? Serial.println(F("Failed to read from DHT sensor! If you are trying to split the text in the textbox then. (Ep. String to const char* using "string.c_str ();" - Arduino Forum arduino ide - Cannot convert 'String' to 'uint8_t {aka unsigned char { Is there a distinction between the diminutive suffices -l and -chen? Would a room-sized coil used for inductive coupling and wireless energy transfer be feasible? 4. strlen () is for C const char* strings. It's basically a bug in the library which is expecting "char *" when you are supplying "const char *. rev2023.7.7.43526. else if (bluetooth_Buffer[13]!=']') (or how to pass a Char String into a Function to behave like a Variable), Converting c string to integer to unsigned char. Convert std::string to const char* in C++ | Techie Delight The returned pointer is backed by the internal array used by the string object, and if the string object is modified, the returned pointer will also be invalidated. To learn more, see our tips on writing great answers. The MQTT_ROOT is changeable, the "MQTT_GetTemperature" is fix and not changable The problem is, expected is a "const char*", but i have only a string. iot - Problem with "converting a string constant to 'char*'" in the rev2023.7.7.43526. WiFi.begin (ssid, password); Share Improve this answer Follow answered Jun 21, 2017 at 20:00 Edgar Bonet Arduino | Delft Compile error - cannot convert 'String' to 'const char - esp8266 Find centralized, trusted content and collaborate around the technologies you use most. Arduino Convert String to Char | Delft Stack Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. Why did Indiana Jones contradict himself? Serial.print("Humidity: "); Serial.print(h); String fireHumid = String(h) + String("%"); //convert integer humidity to string humidity Serial.print("% Temperature: "); Serial.print(t); Serial.println("C "); String fireTemp = String(t) + String("C"); //convert integer temperature to string temperature delay(4000); Firebase.pushString("/DHT11/Humidity", fireHumid); //setup path and send readings Firebase.pushString("/DHT11/Temperature", fireTemp); //setup path and send readings. How can I remove a mystery pipe in basement wall and floor? Personally, I'd like to know what you 'think' you're doing here? 1. Why on earth are people paying for digital real estate? my challenge was just simply putting 1 rfid id in a text file where when i tap my rfid it would just print access granted or denied. Ask Question Asked 11 years, 6 months ago Modified 5 years, 2 months ago Viewed 50k times 12 I have a variable tweet that is a string and it has a character at the very beginning that I want to clip off. So you can use your convertion functions:. How can I learn wizard spells as a warlock without multiclassing? WEMOS D1 Mini / esptool / Failed to connect - Timed out. Does being overturned on appeal have consequences for the careers of trial judges? Other than Will Riker and Deanna Troi, have we seen on-screen any commanding officers on starships who are married? 2. How can I learn wizard spells as a warlock without multiclassing? Stack Exchange network consists of 182 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. No, I was using the same operator the OP used. "); delay(500); } Serial.println(); Serial.print("Connected to "); Serial.println(WIFI_SSID); Serial.print("IP Address is : "); Serial.println(WiFi.localIP()); //print local IP address Firebase.begin(FIREBASE_HOST, FIREBASE_AUTH); // connect to firebase dht.begin(); //Start reading dht sensor}, void loop() { float h = dht.readHumidity(); // Reading temperature or humidity takes about 250 milliseconds! The neuroscientist says "Baby approved!" It only takes a minute to sign up. to be honest im starting on doing random things just to make it work now . Please add that to your question, C:\Users\mrtas\Desktop\sketch_may23a\sketch_may23a.ino: In function 'void setup()': C:\Users\mrtas\Desktop\sketch_may23a\sketch_may23a.ino:38:24: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] WiFi.begin(SSID, PASS); //Begin WiFi ^ ^, 1. If you really wanted to, you could do strlen(s.c_str()), but std::string has a lot of functionality, including a length() method, which returns the number of characters in the string, You do not modify the string within the function so better pass a const reference to it(const string& s), The string itself defines methods for getting its length - s.size() and s.length() both will work. The String class has a (poorly named) toInt() method that will convert the String to an int. Long story short : i'm having trouble with these 2 lines : temp_string=bluetooth_Buffer.substring(9,13); List<string> stringlist = new List<string> (); stringlist.Add (tb.Text); You can use std::string::c_str () function, which returns a pointer to a const char buffer: String card = "2-3d-fg-d6-12-68-32-3f-35-45-42-53-2a-3"; char *prefix = "GET /insert.php?card="; char *postfix ="&error=1 HTTP/1.1\r\nHost: testsite.com\r\n\r\n"; String url = prefix +card+ postfix; const char *url_complete = url.c_str (); //. If you want a float, you can use atof in conjunction with the toCharArray method: Powered by Discourse, best viewed with JavaScript enabled. 11 Hi can any one tell what wrong with this code ?. All rights reserved. cannot convert 'String' to 'const char*' for argument '1' to 'int atoi (const char*)' " I honestly don't understand why because the .substring method should give me a string which should be used by atoi, soo as far as i know there shouldn't be problem with that. How to play the "Ped" symbol when there's no corresponding release symbol. Making statements based on opinion; back them up with references or personal experience. Does being overturned on appeal have consequences for the careers of trial judges? I have this function and the compiler yells at me saying "Cannot convert string to const char". Book set in a near-future climate dystopia in which adults have been banished to deserts, My manager warned me about absences on short notice. convert a string to char for Arduino Ask Question Asked 1 year, 9 months ago Modified 1 year, 9 months ago Viewed 718 times -1 When I write String abc ="0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff"; const unsigned char displaydata []= {reinterpret_cast<const unsigned char*> (abc.c_str ())}; Firebase_temperature:52:12: error: 'class Firebase_ESP_Client' has no member named 'pushString'; did you mean 'toString'? arduino char*const char*string - CSDN here is my code. 1 Hey all I am trying to convert a string into a uint8_t with the following code: String data = "#255101987"; String tmp1 = data.substring (1, 3); uint8_t first = (String)tmp1; I am getting the error of: cannot convert 'String' to 'uint8_t {aka unsigned char}' in initialization string s=getString (); //return string if (!strcmp (s,"STRING")) { //Do something } while compiling I am getting the error like error: cannot convert 'std::string' to 'const char*' for argument '1' to 'int strcmp (const char*, const char*)'| c++ Share Improve this question Follow To learn more, see our tips on writing great answers. Can we use work equation to derive Ohm's law? Cannot assign Ctrl+Alt+Up/Down to apps, Ubuntu holds these shortcuts to itself. If you want a float, you can use atof in conjunction with the toCharArray method: c_str() will give you the string buffer const char* pointer.. 587), The Overflow #185: The hardest part of software is requirements, Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood. Please include an example string from the servers answer to the request. arrTeamMembers [0] = tb.Text; You probably want to use a List instead. How to passive amplify signal from outside to inside? Thanks for contributing an answer to Arduino Stack Exchange! Thanks for contributing an answer to Stack Overflow! Connect and share knowledge within a single location that is structured and easy to search. If you want to stick with String, use "+" instead of sprintf. I am trying to pass the values from tb.Text to arrTeamMembers. does the compilation actually abort? Is my Wemos D1 Mini busted? By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. 52 | Firebase.pushString("/DHT11/Temperature", fireTemp); //setup path and send readings, cannot convert 'const char [28]' to 'FirebaseConfig*' {aka 'fb_esp_cfg_t*'}, This report would have more information with, #include