题解 | 统计字符

#include <iostream>
#include <vector>
#include <string>

using namespace std;

int main(){
    string str;
    vector<int> res(4);
    if(std::getline(cin,str)){
        for(auto &ch: str){
            if(isalpha(ch)){
                res[0]++;
            }else if(ch == ' '){
                res[1]++;
            }else if(isdigit(ch)){
                res[2]++;
            }else{
                res[3]++;
            }
        }
        // 进行输出
        for(auto &count: res){
            cout<<count<<endl;
        }
    }
    return 0;
}