text: #include <windows.h>
  #include <stdio.h>
  
  int main(int argc, char* argv[] ){
      char defaultMessage[] = "Hello world!";
      char base[] = "Hello there";
      char *message = NULL;
      char *buffer = NULL;
  
      if (argc == 2){
          size_t nameLen = strlen(argv[1]);
          buffer = (char*) malloc( strlen(base) + strlen(argv[1]) + 3);
          sprintf(buffer, "%s %s!", base, argv[1]);
          message = buffer;
      } else{
          message = defaultMessage;
      }
  
      MessageBoxA(NULL, message, "Greetings!", MB_OK);
      
      if(buffer != NULL){
          free(buffer);
      }
      return 0;   
  }