Find a Substring

The conventional way of finding a substring with size m in a string of n characters is implemented here, the performance is m*n and not really exciting. A better approach is using a data structure called “Suffix Array”

 #include  #include   using namespace std;  int find_substring(const char* mainString, const char* subString) {   assert(mainString);   assert(subString);    int iFoundIndex = 0;    const char* subPointer;   bool bFound;    for(; *mainString != 0; mainString++, iFoundIndex++)   {     for(bFound = true, subPointer = subString;       *subPointer != 0;       ++subPointer)     {       if(*(mainString + ((int)subPointer - (int)subString))               != *subPointer)       {         bFound = false;         break;       }     }      if(bFound)       return iFoundIndex;   }    return -1; }