why does my ide shows error saying unsupported operand types?-CodePudding

def intToBin(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    elif n > 1:
        return ((n % 2   10 * intToBin((n/2))))

a = 6
b = intToBin(a)
print(b)

CodePudding user response：

You need to pass int(n/2) into function because if n/2 is floating it will cause an error in code when the value is less than 1. see below solution

def intToBin(n): 
    if n == 0: 
        return 0 
    elif n == 1: 
        return 1 
    elif n > 1: 
        return ((n % 2   10 * intToBin(int(n/2))))

a = 6
b = intToBin(a) 
print(b)

OUTPUT :

CodePudding user response：

Your code:

def intToBin(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    elif n > 1:
        return ((n % 2   10 * intToBin((n/2))))

a = 6
b = intToBin(a)
print(b)

In python3, n/2 is a float division operation. So in recursive call, a float is being passed. Now when this float is less than 1, there is no if-else block that satisfies the condition, hence the function returns None. The multiplication of 10 with None from the recursive call results in error.

For debugging and better understanding, print n:

def intToBin(n):
    print(n)
    ...rest of your code

which outputs:

6
3.0
1.5
0.75
Traceback (most recent call last):
  File "zz.py", line 11, in <module>
    b = intToBin(a)
  File "zz.py", line 8, in intToBin
    return ((n % 2   10 * intToBin((n/2))))
  File "zz.py", line 8, in intToBin
    return ((n % 2   10 * intToBin((n/2))))
  File "zz.py", line 8, in intToBin
    return ((n % 2   10 * intToBin((n/2))))
TypeError: unsupported operand type(s) for *: 'int' and 'NoneType'

To fix:
As answered above, either use int(n/2) or n//2 or have a default base or return case of the function.