JS基础语法---函数练习part1---5个练习

练习1：求两个数字的和:获取任意的两个数字的和

      function getSum(x, y) {
        return x + y;
      }
      console.log(getSum(10, 20));

练习2：求1-100之间所有的数字的和

      function geteverySum() {
        var sum = 0;
        for (var i = 1; i <= 100; i++) {
          sum += i;
        }
        return sum;
      }
      console.log(geteverySum());

练习3：求1-n之间所有数的和

      function geteverySum(n) {
        var sum = 0;
        for (var i = 0; i <= n; i++) {
          sum += i;
        }
        return sum;
      }
      console.log(geteverySum(89));

练习4：求n-m之间所有数的和

      function geteverySum2(n,m) {
        var sum = 0;
        for (var i = n; i <= m; i++) {
          sum += i;
        }
        return sum;
      }
      console.log(geteverySum2(32,90));

练习5：求圆的面积

      function geteverySum2(n,m) {
        var sum = 0;
        for (var i = n; i <= m; i++) {
          sum += i;
        }
        return sum;
      }
      console.log(geteverySum2(32,90));