简单题,直接做就可以
答案:624
#includeusing namespace std; int num = 0; void fun(int x) { int t; while(x > 0) { t = x % 10; x /= 10; if(t == 2) num++; } } int main() { for(int i = 1; i <= 2020; i++) { fun(i); } cout << num; return 0; }

简单题,直接做就可以
答案:624
#includeusing namespace std; int num = 0; void fun(int x) { int t; while(x > 0) { t = x % 10; x /= 10; if(t == 2) num++; } } int main() { for(int i = 1; i <= 2020; i++) { fun(i); } cout << num; return 0; }