PTA刷题记录：L1-003 个位数统计 (15分)

#include <iostream>
#include <string>

using namespace std;

int main() {
	string str;
	int arr[10]{0}; 
	
	cin >> str;
	
	for (string::iterator p = str.begin(); p != str.end(); p++) {
		switch (*p) {
			case '0': arr[0]++; break;
			case '1': arr[1]++; break;
			case '2': arr[2]++; break;
			case '3': arr[3]++; break;
			case '4': arr[4]++; break;
			case '5': arr[5]++; break;
			case '6': arr[6]++; break;
			case '7': arr[7]++; break;
			case '8': arr[8]++; break;
			case '9': arr[9]++; break;
		}
	}
	for (int i = 0; i < 10; i++) {
		if (arr[i] != 0) {
			cout << i << ":" << arr[i] << endl;
		}
	}
	
	return 0;
}