while循环外的else语句

Question

I'm trying to fit a if and an else statement inside a while loop that's reading data.

Here's the simplified code:

char customColor;
cin >> customColor;   
while (!ws(file).eof())
{
 file >> color;
    if (customColor == color)
    {
    //////////////////
    }
    else
        cout << "invalid color" << endl;
}

The thing is that the console writes "invalid color" whenever what I've entered doesn't match what's in the file and what I'm trying to do is to write "invalid color" only when no results in the text file match the color that I've input.

I was wondering if there was any way to put the else statement outside of the while loop.

Answer 1

You could probably use the if else statement to set a bool to check whether no results in the text file match the color that you have input.

char customColor;
cin >> customColor;

bool check = false;

while (!ws(file).eof())
{
    file >> color;
    if (customColor == color)
    {
       check = true;
    }
}

if (!check)
{
    cout << "invalid color" << endl;
}

Answer 2

if there was any way to put the else statement outside of the while loop.

You can't do that directly, but you could make a flag variable and do some bookkeeping for it.

char customColor;
cin >> customColor;   
bool matched = false;
while (!ws(file).eof())
{
  file >> color;
  if (customColor == color)
  {
    //////////////////
    matched = true;
  }
}

if (!matched) {
  cout << "invalid color" << endl;
}