前端之js求和

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/qq_36251118/article/details/81261191

var arr=[1,2,3,,4,5,6,7,8,9,10];//将每个元素求和

共10种方法：

    var sum1 = 0;
    for (var i = 0; i < num.length; i++) {
        sum1 += num[i];
    }
    console.log(sum1);

    var sum2 = 0;
    for(var i in num){
            sum2 += num[i]
    }
    console.log(sum2);

    var sum3 = 0,i = 1;
    while(i<=100){
        sum3 += i;
        i++;
    }
    console.log(sum3);

    var sum4 = 0,i = 1;
    do{
        sum4 += i;
        i++;
    }
    while(i<=100);
    console.log(sum4);

    function sum5(i){
        if( i === 1 ){
            return 1
        }
        return sum5(i-1)+i;
    }
    console.log(sum5(100));

    var sum6 = eval(num.join("+"));
    console.log(sum6);

    var sum7 = num.reduce((t,i)=>t+=i,0);
    console.log(sum7);

    var sum8 = 0;
    num.map((i)=>sum8+=i);
    console.log(sum8);

    var sum9 = 0;
    num.forEach((i)=>sum9+=i);
    console.log(sum9);

    var sum10= 0;
    num.filter((i)=>sum10+=i);
    console.log(sum10);