题解 | #[NOIP2010]数字统计#

#include <stdio.h>

int totalnum(int x, int y)//统计次数函数
{
    int i;
    int k = 0;//计数
    for (i = x; i <= y; i++)
    {   int d = i;
        while(d != 0)
        {
            int e = d % 10;
            if (e == 2)
            {
                k++;
            }
            d = d / 10;
        }
    }
    return k;
}

int main() {
    int a, b;
    scanf("%d %d", &a, &b);//输入范围
    int c = totalnum(a, b);
    printf("%d\n", c);//打印
    return 0;
}