Strings not equal after converting-CodePudding

I have a char message and when i convert it to string and using if statement , return false. and when i use compareTo function returns 175, but it should be 0.

char message[dataSize] ;
// message is ASDFGT
String id = "ASDFGT"
if (String(message) == id){
Serial.println("Strings are equal")
}

i think the problem is converting char to string but how can i handle that?

Serial.println(String(message).compareTo(id));
//returns 175 but it should be 0

and ihave the same problem in python

CodePudding user response：

char array and string object is different objects, equals function compare thats pointers, you need to convert char array into string object and then compare it

char message[dataSize];
String id = "ASDFGT";
  
if (String(message) == id){
  Serial.println("Strings are equal");
}

CodePudding user response：

The syntax of compareTo is

myString.compareTo(myString2)

which returns:

a negative number: if myString comes before myString2
0: if myString equals myString2
a positive number: if myString comes after myString2

char message[dataSize];
String id = "ASDFGT";
  
if (String(message).compareTo(id) == 0)
{
    Serial.println("Strings are equal");
}

The reference is here.

CodePudding user response：

Thanks to @mmixLinus there was a '\0' character at the end. Problem solved