The Print statements don't show up in the C++ game - c++

Question

So I am trying to code a game using C++. I am using this online compiler so I can also work on it at school. This program was just a simple clicker game that I starting making. When I tested it to see if the code worked so far, nothing showed up, which is strange considering I have print statements in the code that give the directions for the player.
#include <iostream>
#include <stdio.h>
using namespace std;
int main()
{
int SCORE = 0;
int LEVEL = 1;
int COST = 50;
int ADDSCORE = 10;
char KEYINPUT;
bool GAMEON = true;
printf("Press space bar to gain points to your score.\n");
printf("Press z key to upgrade your score multiplyer.\n");
printf("Press the escape key (esc) to quit.\n");
printf("Upgrade score multiplyer = %d.\n", COST);
printf("Score multiplyer = LV%d.\n", LEVEL);
printf("Score = %d.\n", SCORE);
while (GAMEON == true) {
if (KEYINPUT == 32) {
SCORE += ADDSCORE;
}
if (KEYINPUT == 122) {
ADDSCORE += 10;
SCORE -= COST;
COST *= 2;
LEVEL += 1;
}
if (KEYINPUT == 27) {
GAMEON = false;
}
}
printf("Game has ended. You may now close out of the game");
return 0;
}
I am not sure if it is my code or if it is the online compiler, but I executed on a different compiler and got the same result. Nothing. Not exactly sure why this is happening, but if someone can spot what is wrong can you let me know.

Answer 1

I tried a bit around and on my system with a local compiler the text also does not print. Now in the first place if you want to code in C++ you need to use C++. printf is actually a C function. You are not using any C++ specific code in your example. If you want to use C in your C++ application though, use the C++ equivalents of the C libraries which wourld be <cstdio> in your case. Now to the problem itself: i am using MSYS shell on windows and i assume you use something similar. There seems to be a problem with the output buffer when you use printf. Normally the output buffer is flushed with the \n newline character at the end of the input. Apparently this does not seem to work in some cases. Adding an fflush(stdout) at the end of the output worked in my case and the text was printed from the buffer and also calling it directly from windows command line, without flushing the buffer, did the trick. So i think it is a problem how your shell handles the buffers. Now to the solutions. Either you flush the output buffer everytime you want to print or you start to use C++ IO. Also as mentioned you need to initialize and change the value from KEYINPUT while your program is running.
#include <iostream>
using namespace std;
int main()
{
int SCORE = 0;
int LEVEL = 1;
int COST = 50;
int ADDSCORE = 10;
char KEYINPUT;
bool GAMEON = true;
/* Use cout instead of printf for output operations */
cout << "Press space bar to gain points to your score." << endl
<< "Press z key to upgrade your score multiplyer." << endl
<< "Press the escape key (esc) to quit" << endl
<< "Upgrade score multiplyer = " << COST << endl
<< "Score multiplyer = LV" << LEVEL << endl
<< "Score = " << SCORE << endl;
while (GAMEON == true) {
KEYINPUT = cin.get(); /* You need to initialize the value before using and change it in the loop */
if (KEYINPUT == 32) {
SCORE += ADDSCORE;
}
if (KEYINPUT == 122) {
ADDSCORE += 10;
SCORE -= COST;
COST *= 2;
LEVEL += 1;
}
if (KEYINPUT == 27) {
GAMEON = false;
}
}
cout << "Game has ended. You may now close out of the game" << endl;
return 0;
}
A little note at the end: Since i tried to do similar little games as i started, you will need to use a platform dependent library to capture those keystrokes like ESC or other keys which not directly get put into the input buffer. i know conio for windows and otherwise the winapi is well documented and relatively easy to use. There are also many examples of how to use the winapi to capture keystrokes from the command line window which can easily be found on google.