• C

compare strings

how to compare two strings using pointers
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evilrixSenior Software Engineer (Avast)Commented:
Yup.  The syntax would be strcmp(var1, var2);

Note, the strcmp function returns 0 (false) if the strings are identical, and >0 (true) if they are not.  This is opposite of what one would think.  So, if you are using an if statement to branch conditionally if they are the same, you would use the not operator (!).

if( ! strcmp(var1, var2)) ...
I assume you mean how do you write actual code, not by calling a library function.

The general method is:  while the two characters are equal and not the ending zero byte, bump the pointers.  If you end up with both pointers pointing to a zero byte, the strings are equal.  Any other case means the strings are not equal.  Code is something like this:

while( *s1 != '\0'  &&  *s2 !=  '\0' && *s1 == *s2 ) { s1++; s2++}

return *s1 == '\0' &&  *s2 == '\0';


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