Untitled

using cstring in c   program isnt running whats wrong? [closed]
#include <iostream>
#include <cstring>

using namespace std;

void DisplayAllUpper(char& Days);
void DisplayFirstUpper(char& Days);
void DisplayDaysLength(char& Days, int x);

int main()
{
    char Days[5][10]={"monday", "tuesday", "wednesday", "thursday", "friday"};//array of days
    int x;

    DisplayAllUpper(&Days);
    DisplayFirstUpper(&Days);
    DisplayDaysLength(&Days, x);

    return 0;
}

void DisplayAllUpper(char& Days)
{
    //Part a: Change Days to all Uppercase
    cout<<"Part A" <<endl;
    cout << endl;
    for(int i=0; i<5; ++i)
    {
        strupr(Days[i]);
        cout << Days[i]<<endl;
    }
}

void DisplayFirstUpper(char& Days)
{
    //Part B: Change the first letter of each Day to Uppercase
    cout<<"Part B" << endl;
    cout << endl;
    for(int i = 0; i < 5; ++i)
   {
       Days[i][0] = toupper(Days[i][0]);
       cout<<Days[i]<< endl;
   }
}

void DisplayDaysLength(char& Days, int x)
{
    //Part C: Show Day of the week and how many letters each day of the week is
    cout<< "Part C" <<endl;
    cout << endl;
    for(int i=0; i<5; ++i)
    {
        int x= strlen(Days[i][0]);
        cout << x << endl;
    }
}