编辑代码

#include <stdio.h>
#include <string.h>
int mycmp(const char*s1,const char *s2){
    /*int idx =0;
    while(s1[idx]==s2[idx]&&s1[idx]!='\0'){
        idx ++;
    }*/
   while(*s1==*s2 &&*s1 !='\0'){
       s1++;
       s2++;
   }
    return *s1-*s2;
}
int main (int argc,char const *argv[]) {
   char s1[]="abc";
      char s3[]="Abc ";
      char s4[]="bbc ";

   char s2[]="abc ";
   printf("%d\n",mycmp(s1,s2));
      printf("%d\n",mycmp(s1,s3));
      printf("%d\n",mycmp(s1,s4));

   printf("%d\n",'a'-'A');
    return 0;
}