> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> 
> int SafeStrCpy2KeyWord(char * dest, char * source,int size,char* key)
> {
> 	if(strcmp(key,"NULL") == 0)
> 	{
> 		strcpy(source,"NULL");
> 		return 0;
> 	}
> 
> 
> 	char * p=strstr(dest,key);
> 	int n=p-dest;
> 	if(n==0)
> 	{
> 		strcpy(source,dest);
> 		return 0;
> 	}
> 	strncpy(source,dest,n);
> 	source[n]='\0';
> 	return n;
> }
> int main()
> {
> 	char dest[256],key[256],source[256];
> 	while(scanf("%s",dest)!=EOF)
> 	{
> 		int size=strlen(dest);
> 		scanf("%s",key);
> 		while(strcmp(key,"END")!=0)
> 		{
> 			int len=SafeStrCpy2KeyWord(dest,source,size,key);
> 			printf("%d %s\n",len,source);
> 			scanf("%s",key);
> 		}
> 	}
> 	return 0;
> }
能用strstr，我就是用的那个，AC了的