cppreference.com > C/C++ Keywords > while while Syntax:
      while( condition ) {
      statement-list;
      }
The while keyword is used as a looping construct that will evaluate the statement-list as long as condition is true. Note that if the condition starts off as false, the statement-list will never be executed. (You can use a do loop to guarantee that the statement-list will be executed at least once.) For example:
       bool done = false;
       while( !done ) {
         ProcessData();
         if( StopLooping() ) {
           done = true;
         }
       }
Related topics: break continue do for if