l33t.cpp

#include <iostream>
#include <string.h>
#include <thread>
#include <unordered_map>

const int THREAD_MAX = 8;
std::unordered_map<char,char> leet = {{'a','@'},{'e','3'},{'l','1'},{'o','0'},{'s','$'}};

void leetify(char* input, int start, int step){
  std::unordered_map<char,char>::iterator it;

  while(start<strlen(input)){
    it = leet.find(*(input+start));
    if(it != leet.end()){
      *(input+start) = (*it).second;
    }
    start+=step;
  }
}

int main(int argc, char *argv[]){
  if(argc < 2){
    std::cout << "Requires an Input String" << std::endl;
    return 0;
  }
  char* input = argv[1];

  std::thread t[THREAD_MAX];
  for(int x=0; x<THREAD_MAX; x++){
    t[x] = std::thread(leetify,input,x,THREAD_MAX);
  }
  for(int x=0; x<THREAD_MAX; x++){
    t[x].join();
  }

  std::cout << input << std::endl;

}