没写清楚需求啊‘求字串’是什么意思？可以用库函数不？刚回错地方了，好像：求串长,strlen(str),连接strcat(s1,s2),求字串strstr(s1,s2)程序代码：int main(void){
char s1[] = "if youwant someshing";
char s2[] = “please do something”;
char substring[64];
int ret = 0;
// 串长
printf("len of s1 is %d, len of s2 is %d.\n", sizeof(s1), sizeof(s2));
//... |
