编写程序，计算1+2+3+…..+100的值

int a1=1;
int a2=2;
int a3=3;
int a100=100;
a100=a1+a2+....+a100;

语法

while(条件表达式){
    循环体
}

class Demo{
    public static void main(String[] args){
        int counter = 1;
        int sum = 0;
        while(counter <= 100){
            //sum = sum + counter;
            sum += counter;
            counter++;
        }
        System.out.println("1+2+....+100=" + sum);
    }
}