判断一个字符串在另一个字符串中出现的次数.c

#include<stdio.h>
int main(){ char s[1024]=""; char key[1024]=""; printf("input a strings for s\n s = "); scanf("%s",s); printf("input a strings for key\n key = "); scanf("%s",key); int i,j,m, sum =0; for(i=0;s[i];i++)   //s[i]要从头遍历到尾 {
for(m=i,j=0;key[j]&&key[j]==s[m];j++,m++); //for循环带分号，即当key[j]&&key[j]==s[m]成立时，执行j++,m++,否则立即退出，本实验中key[m]大多数并不等于s[m]所以会立即停止，key不走到头 if(key[j]=='\0')  sum++ ;     }          if (sum!=0)  printf ("key appears %d times\n",sum );  else   printf ("key is not in s \n"); return 0;}