题解 | #统计字符#

#include <iostream>
using namespace std;
int main()
{
    int a[4] = {};
    string input;
    getline(cin, input);
    for (auto it = begin(input); it != end(input); ++it)
    {
        if (isalpha(*it))
        {
            a[0]++;
        }
        else if (isspace(*it))
        {
            a[1]++;
        }
        else if (isdigit(*it))
        {
            a[2]++;
        }
        else
        {
            a[3]++;
        }
    }
    for (int i = 0; i <= 3; i++)
        cout << a[i] << endl;
    return 0;
}