java基础—求和

此篇文章希望帮助一些自学Java的小白 (如果有疑问可以留言)
1.求0-100整数的和

public static void main(String[] args) {        int sum = 0;        for (int i = 0; i < 101; i++) {            sum = sum + i;        }        System.out.println("sum=" + sum);    }

2.求0-100奇数的和

public static void main(String[] args) {        int sum = 0;        for (int i = 0; i < 101; i++) {            if (i % 2 != 0) {                sum = i + sum;            }        }        System.out.println("sum=" + sum);    }

3.求0-100偶数的和

public static void main(String[] args) {        int sum = 0;        for (int i = 0; i < 101; i++) {            if (i % 2 == 0) {                sum = i + sum;            }        }        System.out.println("sum=" + sum);    }

4.求100以内的质数以及他们的和

public static void main(String[] args) {        int sum=0;        for (int i = 2; i <= 100; i++) {            boolean flag = true;            for (int j = 2; j < i; j++) {                if (i % j == 0) {                    flag = false;                    break;                }            }            if (flag) {                System.out.println(i);                sum=sum+i;            }        }        System.out.println(sum);    }