1、for循环

int sum = 0;

for (int i = 1; i <= 100; i++) {
sum += i;
}
System.out.println(“1到100累加的和为：” + sum);

2、while循环

int sum = 0;
int i = 1;
while (i <= 100) {
sum += i;
i++;
}
System.out.println(“1到100累加的和为：” + sum);

3、do…while循环

int sum = 0;
int i = 1;
do {
sum += i;
i++;
} while (i <= 100);
System.out.println(“1到100累加的和为：” + sum);