c++ h/w others

#include <iostream>
#include <string>
#include <algorithm>

using namespace std;


void fifth ()
{
string s;
getline(cin,s);
string str = s;
for (int i = 0; i < s.size();i++){
str[i] = s[s.size() - i - 1];
}
if ( s == str){
cout << "YES";}
else{
cout << "NO";
}
}


void fourth ()
{
    int y,t =1;
    string p;
    getline(cin,p);
    y = p.length();
    t = t + count(p.begin(), p.end(), ' ');
    cout << "Result: " << t << endl;
}


void third()
{
    char z;
    cin >> z;
    if ((z >= 97) && (z <= 122)){
        z = z - 32;
        cout << z;
    }else {
       // if ((z >= 65) && (z <= 90)){
            z = z + 32;
        cout << z;
    }
}


void second()
{
    char m;
    cin >> m;
    m -= 32;
    cout << m;
}


void first()
{
    string s;
    cin >> s;
    if ((s == "0") && (s == "9") && (s == "1") && (s == "2") && (s == "3") && (s == "4") && (s == "5") && (s == "6") && (s == "7") && (s == "8")){
            cout << "Yes";
    }
    else
    {
        cout << "No";
    }
}

int main()
{
int u;
cout << "vvedite nomer zadachi" << endl;
cin >> u;
if (u == 1){
first();
}
if (u == 2){
second();
}
if (u == 3){
third();
}
if (u == 4){
fourth();
}
if (u == 5){
fifth();
}
}