Do-While to ask user to repeat entire int main programme - c++

Question

Very new to programming and l can't find any basic explanation online or code that will work well for what l need. I have a fairly long piece of programme (approx 300 lines) it all works. This is the structure to give an idea:
#include <iostream>
#include <stdlib.h>
#include <time.h>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
//code....
{
//code... etc...
}
}
I want to ask the user to repeat the programme. If enters y, then repeat int main up to the point of asking the same repeat question again. Else to cout<< "e.g. Thank you, goodbye";

Answer 1

#include <iostream>
#include <stdlib.h>
#include <time.h>
#include <vector>
#include <algorithm>
//using namespace std; <--- Don't use using namespace std, it pollutes the namespace
void repeat()
{
//... code to repeat
}
int main()
{
//code....
char answer;
while((std::cin >> answer) != 'y')
{
repeat();
}
}

Answer 2

#include <iostream>
#include <conio.h>
using namespace std;
//Class
class DollarToRs {
public:
int Dollar;
int Rs;
int ToRs;
ConversionToRs() {
cout << "Enter the amount of Dollar: ";
cin >> Dollar;
ToRs = Dollar * 154;
cout << "This is the total amount in PKR: " << ToRs <<endl;
}
};
int main()
{
//Dollar Convertion Function
DollarToRs convert;
convert.ConversionToRs();
//For Repeating Program
int repeat;
int exit;
cout << "To repeat program enter 1" <<endl;
cin >> repeat;
while (repeat == 1) {
convert.ConversionToRs();
cout << "To repeat program enter 1" <<endl;
cin >> repeat;
}
exit =0;
if (exit == 0) {
}
getch();
return 0;
}

Answer 3

Here's an example of a simple solution:
int main()
{
for (;;) // "infinite" loop (while (true) is also possible)
{
// stuff to be repeated here
cout << "Repeat? [y/n]" << endl;
char answer;
cin >> answer;
if (answer == 'n')
break; // exit loop
} // else repeat
cout << "Thank you, goodbye" << endl;
}
Here's another one:
int main()
{
bool repeat = true;
while (repeat)
{
// stuff to be repeated here
cout << "Repeat? [y/n]" << endl;
char answer;
cin >> answer;
repeat = answer == 'y';
}
cout << "Thank you, goodbye" << endl;
}
As a side note, don't do this: #include <stdlib.h>. In C++ you should use the c prefixed header file names when using the C headers: #include <cstdlib> and #include <ctime>.