Question

This gets the job done for what I need it to do, but I am wondering if there is an easier/more efficient way of accomplishing the same thing. The user inputs two numbers and they need to be between 0 and 50, if it doesnt fall within the required range it ends the prog

cout << "Enter the pixel coordinate (x, y): ";
cin >> usrInput1 >> userInput2;
if  (usrInput1 > 50)
{
    cout << "ERROR! 1" << endl;
    return 0;
}
else if (usrInput1 < 0)
{
    cout << "ERROR! 2" << endl;         
    return 0;
}
else if (usrInput2 > 50)
{
    cout << "ERROR! 3" << endl;
    return 0;
}
else if (usrInput2 < 0)
{
    cout << "ERROR! 4" << endl;
    return 0;
}
else
{
    cout << "Success" << endl;
    xvar = usrInput1 + usrInput2;
}

I was trying to do something like

if(! 0 > userInput1 || userInput2 > 99)

but obviously that didn’t work out..

Thanks for any assistance

Answer 1

cout << "Enter the pixel coordinate (x, y): ";
cin >> usrInput1 >> userInput2;
if  ( (usrInput1 > 50) || (usrInput1 < 0)  ||
      (usrInput2 > 50) || (usrInput2 < 0) )
{
    cout << "ERROR!" << endl;
    return 0;
}
cout << "Success" << endl;
xvar = usrInput1 + usrInput2;

You could actually combine it further if you really wanted:

if  ((std::max(usrInput1,usrInput2) > 50) 
   || std::min(usrInput1,usrInput2) < 0))
{ 
     ...

in which case I would rather have a helper function

bool isValid(int i) { return (i>=0) && (i<=50); }

// ...
if (isValid(usrInput1) && isValid(usrInput2))
    ...

Edit Consider checking the input operations – this was missing in the OP:

if (!(cin >> usrInput1 >> userInput2))
{
     std::cerr << "input error" << std::endl;
}
if  ( (usrInput1 > 50) || (usrInput1 < 0)  ||
      (usrInput2 > 50) || (usrInput2 < 0) )
{
     std::cerr << "value out of range" << std::endl;
}