Implement the strcmp(str1, str2) function.

There are many ways one can implement the strcmp() function. Note that strcmp(str1,str2) returns a -ve number if str1 is alphabetically above str2, 0 if both are equal and +ve if str2 is alphabetically above str1.

Here are some C programs which implement the strcmp() function. This is also one of the most frequently asked interview questions. The prototype of strcmp() is


int strcmp( const char *string1, const char *string2 );



Here is some C code..


#include

int mystrcmp(const char *s1, const char *s2);

int main()
{
printf("\nstrcmp() = [%d]\n", mystrcmp("A","A"));
printf("\nstrcmp() = [%d]\n", mystrcmp("A","B"));
printf("\nstrcmp() = [%d]\n", mystrcmp("B","A"));
return(0);
}

int mystrcmp(const char *s1, const char *s2)
{
while (*s1==*s2)
{
if(*s1=='\0')
return(0);
s1++;
s2++;
}
return(*s1-*s2);
}


And here is the output...


strcmp() = [0]
strcmp() = [-1]
strcmp() = [1]