pat各位数统计

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int a[10]={0};
string s;

int main()
{
    cin>>s;
    int i;

    for(i = 0; i < s.length(); ++i)
        a[s[i]-'0']++;
    for(i = 0; i < 10; ++i)
        if(a[i] != 0)
            cout<<i<<":"<<a[i]<<endl;
    return 0;
}