NZEC error in Python

While coding on various competitive sites, many people must have encountered NZEC errors. NZEC (non-zero exit code), as the name suggests, occurs when your code fails to return 0. When a code returns 0, it means it is successfully executed otherwise, it will return some other number depending on the type of error. When the program ends and it is supposed to return "0" to indicate if it finished fine, and is not able to do so, it causes NZEC. Of course, there are more cases associated with NZEC.

Why does NZEC occur?(one example)

In python, generally, multiple inputs are separated by commas and we read them using input() or int(input()), but most of the online coding platforms while testing give input separated by space and in those cases, int(input()) is not able to read the input properly and shows error like NZEC.

How to resolve?

For Example, think of a simple program where you have to read 2 integers and print them (in the input file, both integers are on the same line). Suppose you have two integers as shown below: 23 45. Instead of using:

n = int(input())
k = int(input())

Use:

n, k = raw_input().split(" ")
n = int(n)
k = int(k)

To delimit input by white spaces.

Wrong code

n = int(input())
k = int(input())
print(n, " ", k)

Input: 2 3

 When you run the above code in the IDE with the above input, you will get the error:-

Traceback (most recent call last):
  File "b712edd81d4a972de2a9189fac8a83ed.py", line 1, in 
    n = int(input())
  File "", line 1
    2 3
      ^
SyntaxError: unexpected EOF while parsing

The above code will work fine when the input is in 2 two different lines. You can test yourself. To overcome this problem, you need to use split.

Correct code

n, k = input().split()
n = int(n)
k = int(k)
print(n, " ", k)

Input:

7 3

Output:

7   3

Some prominent reasons for the NZEC error

1. Infinite Recursion, or if you have run out of stack memory.
2. Input and output are NOT the same as the test cases.
3. On the online platforms, test your program using a computer code that matches your output with the specified outputs exactly.
4. This type of error is also shown when your program is performing basic programming mistakes, like dividing by 0.
5. Check the values of your variables, they can be vulnerable to integer overflow.

There could be some other reasons also for the occurrence NZEC error, I have listed the frequent ones.