Compile and run program after code change

grunt.js

module.exports = function( grunt ) {
  'use strict';

  // Compile and run program after code change
  //
  // Assumptions:
  // 1) One cpp file named 1.cpp
  // 2) One resulting binary a.out compiled with g++

  grunt.initConfig({
    // Project configuration
    // ---------------------

    // watch configuration
    watch: {
      recompile: {
        files: [
          '1.cpp'
        ],
        tasks: 'compile run'
      }
    }
  });

  grunt.registerTask('compile', 'run compiler', function () {
    var done = this.async();
    require('child_process').exec('g++ 1.cpp', function (err, stdout, stderr) {
      grunt.log.write(stdout + stderr);
      done(err);
    });
  });
  grunt.registerTask('run', 'run binary', function () {
    var done = this.async();
    require('child_process').exec('./a.out', function (err, stdout, stderr) {
      grunt.log.write(stdout + stderr);
      done(err);
    });
  });

  grunt.registerTask('default', 'watch');
};