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  to reset your code definition.

 

 1     int strStr(string haystack, string needle) {
 2         int i=0,j=0,k=0;
 3         int lenh=haystack.length();
 4         int lenn=needle.length();
 5         if(lenn>lenh)
 6         return -1;
 7         if(lenn==0)
 8         return 0;
 9         for(i=0;i<lenh-lenn+1;i++)
10         {
11             j=0;k=i;
12             while(haystack[k]==needle[j])
13             {
14                 if(j==lenn-1)
15                 return k-j;
16                 j++;
17                 k++;
18             }
19            
20         }
21        
22         return -1;
23     }