Arduino.Read Serial, create String, search into the string, clean String -

i trying work sim900, trying do, is: 1- read serial port, 2- input string, 3- search parameter in string, 4- clean string. code simple, cant understand doing wrong. if make similar, or knows how graceful. thank jose luis

string leido = " "; void setup(){ // serial1 baud rate      serial.begin(9600); serial1.begin(9600);   }       string leido = " "; void setup(){                  // serial1 baud rate      serial.begin(9600); serial1.begin(9600);   } void loop()     {     //if (serial1.available()) {  serial.write(serial1.read()); } // sim900     if (serial.available()) {  serial1.write(serial.read()); } // pc     leido = leerserial();     serial.println(leido);     if (find_text("ready",leido)==1){leido = " ";}      }       string leerserial(){      char character;      while(serial1.available()) {      character = serial1.read();      leido.concat(character);      delay (10); }       if (leido != "") { serial1.println(leido);return leido; }     }       int find_text(string needle, string haystack) {       int foundpos = -1;       (int = 0; (i < haystack.length() - needle.length()); i++) {         if (haystack.substring(i,needle.length()+i) == needle) {           foundpos = 1;         }       }       return foundpos;     } 

you shouldn't using == compare strings in c/c++, since compares pointers. better option strcmp or better strncmp, check this reference.

back code, try this:

if (strncmp(haystack.substring(i,needle.length()+i), needle, needle.length()) == 0) {   foundpos = 1; }