循环（for\while\do...while）打印1到100的整数加和

    //计算1、2、3、、、100这100个数的整数和
    for语句
    #include<stdio.h>
    int main()
    {
    int a,sum;
    sum = 0;
    for (a = 1; a <= 100; a++)
    {
        sum = sum + a;
    }
    printf("整数和为%d\n",sum);
    }
    //while循环：
    {
    int a, sum;
    sum = 0;
    a = 1;
    while (a <= 100){
        sum +=a;
        a++;
    }
    printf("整数和为%d\n", sum);
    }
    //do...while语句
    {
    int a = 1, sum = 0;
    {
        do{
            sum += a;
            a++;
        }
            while (a <= 100);
        printf("整数和为%d\n", sum);
    }
    }