How do I loop a variable? - c++

Question

I have made a "program" that just says welcome! Type two numbers you want to be added to each other:
there you type the two numbers and then you get the answer out...
When that is done it says: Press any key to continue . . .
When you press a key the program shuts down, but I want it to restart when you pres any key...
How do I do that? I use Microsoft visual studio express 2013 for windows desktop...
langue is C++
This is my code:
#include <iostream>
#include <limits>
#include <cstdio>
using namespace std;
int Add(int x, int y)
{
cout << "Calculating the sum of " << x << " + " << y << "\n";
return (x + y);
}
int main()
{
cout << " Welcome!\n";
int a, b, c;
cout << "Type two numbers you want to be added to each other: ";
cin >> a;
cin >> b;
c = Add(a, b);
cout << "The answere is: " << c;
cout << "\nShutting down....\n\n";
system("pause");
return 0;
}

Answer 1

To loop, you can use while.
For example:
while (false) {
std::cout << "You will never see this output" << std::endl;
}
bool loop = true;
while (loop) {
std::cout << "Type 'quit' to quit this loop." << std::endl;
std::string input;
// This will grab a *single word* from the input. If you want a line, look
// at std::getline
std::cin >> input;
if (input == "quit") {
loop = false;
}
}
while (true) {
std::cout << "This will be repeated forever" << std::endl;
}
There are also two other forms, do while:
std::string input;
do {
std::cout << "Type 'quit' to quit." << std::endl;
std::cin >> input;
} while (input != "quit");
... and for (which is generally used for loop over a defined list of things):
for (size_t i = 0; i < 10; ++i) {
std::cout << i << " out of 10" << std::endl;
}
Technically you can use any of these loop types for any kind of looping, but I suspect the type you want is either one of the two standard infinite loops (whichever one you prefer):
while (true) {
// stuff to repeat forever
}
for (;;) {
// stuff to repeat forever
}
... or a do while loop similar to the do { ... } while (input != "quit"); loop above.

Answer 2

int main()
{
cout << " Welcome!\n";
int a, b, c;
while (true)
{
cout << "Type two numbers you want to be added to each other: ";
cin >> a;
cin >> b;
c = Add(a, b);
cout << "The answere is: " << c;
cout << "\nPress a key to go again....\n\n";
system("pause");
};
return 0;
}

Answer 3

You can do something like this:
int main()
{
cout << " Welcome!\n";
int a, b, c;
while(true) {
cout << "Type two numbers you want to be added to each other: ";
cin >> a;
cin >> b;
c = Add(a, b);
cout << "The answere is: " << c;
cout << "\nPress any key to continue\n";
system("pause");
}
return 0;
}

Answer 4

Use a do while loop mentioning your condition
before exiting the program so that you can determine when to continue and when to exit

Answer 5

I am not sure I understand your question, but I think this is what you are looking for. Have a boolean that determines if the program will loop or not.
int main() {
// stillRun is true while we want to keep looping the program
boolean stillRun = true;
while(stillRun) {
runProgram() ; // this function has all the other code in your old main() function
cin >> stillRun ;
}
}