Count the occurrence of numbers in C++? - c++

Question

I just recently created a code in C++ where I have to display the occurrence of numbers from a text file that I made using this code:
using namespace std;
int main()
{
bool isCovered[99] = {};
int number;
// Read each number and mark its corresponding element covered
while (cin.good())
{
cin >> number;
if (number == 0)
{
break;
}
if ((number >= 1) && (number <= 99))
{
isCovered[number - 1] = true;
}
}
// Check if all covered
bool allCovered = true; // Assumes all covered initially
for (int i = 0; i < 99; i++)
if (!isCovered[i])
{
allCovered = false; //Finds one number not covered
break;
}
// Display result
if (allCovered)
cout << "The tickets cover all numbers" << endl;
else
cout << "The tickets don't cover all numbers" << endl;
return 0;
}
It's not displaying a result, is the program too complex, or is it something that I'm missing?
EDIT: Thanks #selbie for the edit to my code, i was able to figure out that it was a user input but when i put in a zero for the final input. It displays the messages "The tickets don't cover all numbers", why is that?

Answer 1

The bug, if any, is here:
cin >> number;
while (number != 0)
{
isCovered[number - 1] = true;
cin >> number;
}
Two possible issues:
If reading from a redirected file, there's no detection of an end-of-file condition. Such would be the case if the program was invoked as program.exe < input.txt and the input.txt did not contain a 0. Without checking for eof, the program will hang when reading from an input file redirection.
Further, there's nothing to guard against bad input. i.e. numbers outside the range of [1..99]. Without guarding against out of range numbers, undefined behavior will get introduced. Or more likely, the stack will get trashed as a result of inserting into a memory address out of range.
The easy fix is this:
while (cin.good())
{
cin >> number;
if (number == 0)
{
break;
}
if ((number >= 1) && (number <= 99))
{
isCovered[number - 1] = true;
}
}