strcmp in c

int strcmp(const char *str1, const char *str2);

/* Program to understand use of strcmp() */
#include<stdio.h>
#include<string.h>
int main()
{
char str1[15],str2[15];
printf("Enter first string :");
gets(str1);
printf("Enter second string :");
gets(str2);
if(strcmp(str1,str2)==0)
{
printf("Both string is equal");
}
else
{
printf("Both string are not equal");
}
return 0;
}

output:
Enter first string : delhi
Enter second string : belly
Both string are not equal

int astrcmp(char str1[], char str2[])
{
int i;
for(i=0;str1[i]!=null;i++)
{
if(str[i]==’\0′)
{
return 0;
}
}
return(str1[i]-str2[i]);
}