题解

#include<iostream>
#include<cstring>
using namespace std;
string s;
int len;
int c[26];
void menset ()
{
    for (int i = 0;i <= 25;i++)
        {
            c[i] = 0;
        }
}
void scan ()
{
    cin >> s;
    len = s.size();
}
void cntp ()
{
    for (int i = 0;i <= len - 1;i++){
        c[s[i] - 'a']++;
    }
}
bool check (int i)
{
    return c[i] == 0;
}
void print ()
{
    for (int i = 0;i <= 25;i++){
        if (! check(i))
        {
            char k;
            k = 'a' + i;
            cout << k << ":" << c[i] << "\n";
        }
    }
}
int main(){
    menset();
    scan();
    cntp();
    print();
}