求出1/1-1/2+1/3-1/4…..1/100的和

• 求出1/1-1/2+1/3-1/4…..1/100的和

    document.write("求出1/1-1/2+1/3-1/4…..1/100的和：<br>")
    var m = 1;
    var num = 0;
    while (m <= 100) {
        if (m % 2 == 0) {
            num += 1 / (-1 * m);
        } else {
            num += 1 / m;
        }
        m++;
    }

    document.write(num + "<hr>");