题解 | #[NOIP2010]数字统计#

#include <iostream>
using namespace std;

int main() {
    int a = 0, b = 0;
    scanf("%d %d", &a, &b);
    //printf("%d %d", a, b);
    int count = 0;
    for (int j = a; j <= b; j++) {
        int i = j;//这里要注意用个临时变量进行运算
        while(i)
        {

            //cout <<'c'<< i << " ";
            if(i % 10 == 2)
            {
                count++;
            }
            i = i / 10;
            //cout << "b"<< i << " ";
        }

        //cout<< " ccc" << endl;
    }
    cout << count;
    return 0;
}
// 64 位输出请用 printf("%lld")