Can't exit an infinite loop - c++

Question

My program starts by entering any key,then the user sees a color changing text "Welcome to my
program". Now, the user should hit any key to continue, but he can't quit the infinite loop that is changing the color of text. Let me show you the code for a better understanding.
HANDLE color=GetStdHandle(STD_OUTPUT_HANDLE);
cout<<"Press any key to start...";
int stop=getchar();
while(stop){
for(i=10;i<=15;i++){
cout <<("\n\t\t\t\t\t Welcome to my program\n");
SetConsoleTextAttribute(color,i);
Sleep(100);
system("cls");
}
}

Answer 1

This would be a solution for you (comments included)
#include <iostream>
#include <Windows.h>
#include <thread>
int main()
{
HANDLE color = GetStdHandle( STD_OUTPUT_HANDLE );
std::cout << "Press any key to start...";
bool stop = false; // use a Boolean instead of int
// doesn't really matter what the input is, so use getchar().
// Note, this is really just "enter". You can modify if you expect user to
// hit multiple keys before hitting enter
getchar();
// This line here will start a new thread which will wait for the user to hit enter
std::thread getInput = std::thread( [&stop] { getchar(); stop = true; } );
// Loop stays the same (except I inverse the "stop" variable to make more sense)
while ( !stop ) {
for ( int i = 10; i <= 15; i++ ) {
std::cout << ( "\n\t\t\t\t\t Welcome to my program\n" );
SetConsoleTextAttribute( color, i );
Sleep( 100 );
system( "cls" );
}
}
}

Answer 2

When you are using getchar() to get input from the user, it will store inside the integer stop the decimal value of the buffer the user entered.
For example: if the user entered '0', the stop variable will store the value 48 (the decimal value of the char '0').
And you while loop will keep running while stop is not equal to 0, which is never because the decimal value of all of the characters is not 0, the only character that its decimal value is 0 is NULL.
To fix your problem you will need to add an exit option according to your needs.

Answer 3

If you create a loop as follows:
int myInt = 1;
while (myInt)
{
std::cin >> myInt;
}
The loop will continue until the user enters 0. This is because conditional statements use 0 as "false" and in this case, any other value as "true".
The problem with your implementation is you only get the users input once, and even if the user enters "0" (in char format) the integer value associated is 48.
You could add this:
HANDLE color=GetStdHandle(STD_OUTPUT_HANDLE);
cout<<"Press any key to start...";
int stop=getchar();
while(stop){
for(i=10;i<=15;i++){
cout <<("\n\t\t\t\t\t Welcome to my program\n");
SetConsoleTextAttribute(color,i);
Sleep(100);
system("cls");
}
std::cin >> stop;
}
Now the loop will start when the user presses any key, then the the inner loop will run, then the user will need to enter a key again. If the user enters "0" this time the while() loop will break and the program will proceed.
If you are trying to keep a loop running while searching for user input to break the loop, then you are attempting a much more complex task. Look into the std::thread library if you are interested in this.

Answer 4

The issue with your code from what I could tell is that you're only initializing the variable "stop" once in your code and never inside your loop. So, the program will only ask the user for input once. A simple fix would be to continuously ask the user for input at the end of your for loop:std::cin>>stop;. In addition, like what others have already said, if the user inputs '0', it would implicitly typecast the char variable into an integer variable using ASCII. Since '0' corresponds to the integer value of 48, it would save 48 into the variable instead of 0. You can fix this by using this code:
HANDLE color=GetStdHandle(STD_OUTPUT_HANDLE);
cout<<"Press any key to start...";
int stop=getchar()-'0';
while(stop){
for(i=10;i<=15;i++){
cout <<("\n\t\t\t\t\t Welcome to my program\n");
SetConsoleTextAttribute(color,i);
Sleep(100);
system("cls");
}
std::cin>>stop;
}