V663. Infinite loop is possible. The 'cin.eof()' condition is insufficient to break from the loop. Consider adding the 'cin.fail()' function call to the conditional expression.

The analyzer has detected a potential error that may lead to an infinite loop. When you deal with the 'std::istream' class, calling the 'eof()' function is not enough to terminate the loop. If data reading fails, a call of the 'eof()' function will always return 'false'. You need an additional check of the value returned by the 'fail()' function to terminate the loop in this case.

Have a look at an example of incorrect code:

while (!cin.eof())
{
  int x;
  cin >> x;
}

You can fix the error by making the condition a bit more complex:

while (!cin.eof() && !cin.fail())
{ 
  int x;
  cin >> x;
}

However, this option has drawbacks. Correct and the simplest code version looks as follows:

int x;
while(cin >> x) {
  ....;
}

Check out a more detailed discussion on reading from the stream here: Why is iostream::eof inside a loop condition (i.e. 'while (!stream.eof())') considered wrong?

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