Implement StrStr ()

Implement strStr ().

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

• The main idea is to find a short string in the haystack of a large string needle the first occurrence of the position

intSTRSTR (Char* Haystack,Char*needle) {    inti =0, j =0; intHaysize =strlen (haystack); intNeedlesize =strlen (needle); if(Needlesize = =0)        return 0;  while(I <= haysize-needlesize) {        if(* (haystack + i) = = *needle)//find the first same point        {             while(* (needle + j))//on the needle cycle            {                if(* (haystack + i + j) = = * (needle + j))//if the following are the same, continue to judgeJ + +; Else    //the difference jumps out{J=0;  Break; }            }            if(!* (needle + j))//If the judgment is final, the first time that the description appears, return I                returni; } I++; }    return-1;}

• In this topic, the default if needle is empty, return 0

Implement StrStr ()