更新了许多

数字统计.cpp

@@ -0,0 +1,21 @@
+#include <iostream>
+#include <iomanip>
+#include <cstring>
+#include <cstdio>
+#include <ctime>
+using namespace std;
+int main(){
+	int a,b,sum=0;
+	cin >>a>>b;
+	for(int i=a;i<=b;i++){
+		int c=i;
+		while(c){
+			if(c%10==2){
+				sum++;
+			}
+			c/=10;
+		}
+	} 
+	cout <<sum;
+	return 0;
+}