Why does program crash

Question

print ("Prime number tester");
number = input("Enter number: ");
x = 2;
y = 0;

while (x < number):
    if number % x == 0:
        y = y + 1;
        x = x + 1;
    else:
        x = x + 1;



if (y == 0):
    print (number, "is prime.");
else:
    print (number, "isn't prime.");
input();

Why does this crash after I type in the number? Please help as I am new and have no idea why?

@YuriMalheiros there is no error. I open ir as an exe/py doc and it just closes after i enter number — Magna Wise, Mar 08 '15 at 02:28
@OliverMurfett: there is an error, but the console doesn't stay open long enough for you to see it. Run the program from your command line or in IDLE (the IDE that comes with Python). — Martijn Pieters, Mar 08 '15 at 02:31
Take note of which version of Python you are using to run your code. 2 and 3 behave quite differently. — Justin Niessner, Mar 08 '15 at 02:34

score 2 · Accepted Answer · edited May 23 '17 at 11:51

input() in Python 3 returns a string. You cannot compare numbers to strings:

>>> '10' < 10
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unorderable types: str() < int()

Convert the input to an integer first:

number = int(input("Enter number: "))

If the user did not enter a valid number, the int() call raises a ValueError. Depending on how much error handling you want to do, you probably want to catch that exception. See Asking the user for input until they give a valid response for more information on how that'd work.

Python doesn't need those ; semicolons; you can safely remove them from your code.

Why does program crash

1 Answers1