如下情况如果没有，请教哪个慕友帮忙编个这样的函数！

Question

Instr(n,s1,s2)返回在s1字符串中，从第n个字符开始，寻找s2字符，找到返回位置，找不到返回0（s2也可以是字符串（即字符数组）；如果s2长度大于s1，也返回0）如Instr(2,"abcd","c")=3Instr(2,"abcd","cd")=3...

Answer 1

当然有：
#include <string.h>
char *strstr(const char *haystack, const char *needle);

Return
It returns a pointer into the string haystack that is the first character of
the substring, or a null pointer if no match was found. If needle is an empty
string, the function returns haystack.

Description
This is like strchr() , except that it searches haystack for a substring
needle rather than just a single character.

顺便，如果你自己写不出这样的函数，不建议你继续学习C。

Answer 2

没有，有这个函数 
char *strchr(cs, c)
return pointer to first occurrence of c in cs or NULL if not present