PAT 1021 个位数统计 （15 分）

#include<iostream>
#include<map>
using namespace std;
int main() {
    map<int, int> m;
    char ch;
    while (ch = getchar()) {        
        if (ch == '\n')break;
        m[ch -'0']++;
    }
    for (auto it = m.begin(); it != m.end(); it++)
        cout << it->first << ":" << it->second << endl;
    return 0;
}

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