/**
* core idea
* 1.use setting new Array
* 2.fill num1 to num2
* 3.Use the index property in the map method
* (To implement each number between num1 and num2 )
* 4.accumulate
* **/
//come ture addNum
function addNum(num1, num2) {
//estimate max & min
var max = Math.max(num1, num2);
var min = Math.min(num1, num2);
//establish Array
return Array(max - min + 1)//50~60 's individual
//ergodic needed fill
.fill(1)
//mapping new Array
.map(function (item, index) {
//setting menber value
return min + index;
})
//accumulat to find result
.reduce(function (res, item) {
return res + item;//before + next value
}, 0)
}
//test
console.log(addNum(50, 60));//605
console.log(addNum(1, 100));//5050