Implement strStr() strncmp实现strstr()

Implement strStr()

Implement strStr().

Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.

Update (2014-11-02):

The signature of the function had been updated to return the index instead of the pointer. If you still see your function signature returns a ​​char *​​ or ​​String​​, please click the reload button 

class Solution {
public:
    int strStr(char *haystack, char *needle) {
        
        int i,j,len,len1;
        len=strlen(haystack);
        len1=strlen(needle);
        if(len1==0)
            return 0;
        for(i=0;i<=len-len1;i++)
        {
            if(strncmp(haystack+i,needle,len1)==0)
            {
                return i;
            }
        }
        return -1;
    }
};