python calculator program

Question

I wrote a simple calculator program by using functions, I don't know what exactly wrong with this code, its showing error. I did possible steps to debug this, but I couldn't.

#!/usr/bin/python

def add():        
        print "Enter the two numbers to Add"
        A=int(raw_input("Enter A:"))
        B=int(raw_input("ENter B:"))
        c = A + B 

def sub():            
        print "Enter the two numbers to Subtract"
        A=int(raw_input("Enter A:"))
        B=int(raw_input("Enter B:"))
        c = A - B

def Mul():
        print "Enter the two numbers to Multiply"
        A=int(raw_input("Enter A:"))
        B=int(raw_input("Enter B:"))
        c = A * B

def Div():   
        print "Enter the two number to Divide"
        A=float(raw_input("Enter A:"))
        B=float(raw_input("Enter B:"))
        c = A / B

print "1: ADDITION"
print "2: SUBTRACTION"
print "3: MULTIPLICATION"
print "4: DIVITION"
print "0: QUIT"

while true:

    CHOICE = int(raw_input(("ENTER THE CORRESPONDING NUMBER FOR CALCULATION")) 

    if CHOICE == "1": 
        print 'ADDING TWO NUMBERS:'
        add(c):

    elif CHOICE == "2":
        print 'SUBTRACTING TWO NUMBERS:'
        sub(c):

    elif CHOICE == "3":
        print 'MULTIPLYING TWO NUMBERS:'
        Mul(c):

    elif CHOICE == "4":
        print "DIVIDEING TWO NUMBERS"
        Div(c):

    elif CHOICE == "0":
        return 0:

    else
        Print "The value Enter value from 1-4"

Error:

  File "cal_fun.py", line 44
    if CHOICE == "1": 
                  ^
SyntaxError: invalid syntax

Answer 1

I've have tried to cover all of the problems with your code, of which there are numerous.

Starting with syntax errors:

# true needed a captial T
while True:   

    # Brackets were mismatched
    CHOICE = int(raw_input("ENTER THE CORRESPONDING NUMBER FOR CALCULATION")) 

    if CHOICE == "1": 
        print 'ADDING TWO NUMBERS:'
        # Calling a function shouldn't have trailing : 
        add(c)

    elif CHOICE == "2":
        print 'SUBTRACTING TWO NUMBERS'
        # Calling a function shouldn't have trailing :
        sub(c)

    elif CHOICE == "3":
        print 'MULTIPLYING TWO NUMBERS'
        # Calling a function shouldn't have trailing :
        Mul(c)

    elif CHOICE == "4":
        print "DIVIDEING TWO NUMBERS"
        # Calling a function shouldn't have trailing :
        Div(c)

    elif CHOICE == "0":
        # can only return from a function use exit here instead
        exit()

    # else needs a trailing :
    else:
        # No capital P for print
        print "The value Enter value from 1-4"

The code now has no syntax errors but still has many problems.

1. You pass c to your function, c is never initialized, what is c?
2. Your function doesn't take arguments def add(): (even though pass the mysterious c value).
3. Your function doesn't print or return the result it just computes.
4. You store CHOICE as an int are do comparisons with strings so the else case is always executed and there is no way to exit the loop (infinite looping).

---

Fixed code:

#!/usr/bin/python

def add():
        print "Enter the two numbers to Add"
        A=int(raw_input("Enter A: "))
        B=int(raw_input("Enter B: "))
        return A + B 

def sub():
        print "Enter the two numbers to Subtract"
        A=int(raw_input("Enter A: "))
        B=int(raw_input("Enter B: "))
        return A - B

def mul():
        print "Enter the two numbers to Multiply"
        A=int(raw_input("Enter A: "))
        B=int(raw_input("Enter B: "))
    return A * B

def div():
        print "Enter the two number to Divide"
        A=float(raw_input("Enter A: "))
        B=float(raw_input("Enter B: "))
        return A / B

print "1: ADDITION"
print "2: SUBTRACTION"
print "3: MULTIPLICATION"
print "4: DIVITION"
print "0: QUIT"

while True:

    CHOICE = int(raw_input("ENTER THE CORRESPONDING NUMBER FOR CALCULATION ")) 

    if CHOICE == 1: 
        print 'ADDING TWO NUMBERS:'
        print add()

    elif CHOICE == 2:
        print 'SUBTRACTING TWO NUMBERS'
        print sub()

    elif CHOICE == 3:
        print 'MULTIPLYING TWO NUMBERS'
        print mul()

    elif CHOICE == 4:
        print "DIVIDEING TWO NUMBERS"
        print div()

    elif CHOICE == 0:
        exit()
    else:
        print "The value Enter value from 1-4"

---

The code is now functional.

Output:

1: ADDITION
2: SUBTRACTION
3: MULTIPLICATION
4: DIVITION
0: QUIT
ENTER THE CORRESPONDING NUMBER FOR CALCULATION 1
ADDING TWO NUMBERS:
Enter the two numbers to Add
Enter A: 2
Enter B: 5
7
ENTER THE CORRESPONDING NUMBER FOR CALCULATION 2
SUBTRACTING TWO NUMBERS
Enter the two numbers to Subtract
Enter A: 2
Enter B: 5
-3
ENTER THE CORRESPONDING NUMBER FOR CALCULATION 3
MULTIPLYING TWO NUMBERS
Enter the two numbers to Multiply
Enter A: 2
Enter B: 5
10
ENTER THE CORRESPONDING NUMBER FOR CALCULATION 4
DIVIDEING TWO NUMBERS
Enter the two number to Divide
Enter A: 2
Enter B: 5
0.4
ENTER THE CORRESPONDING NUMBER FOR CALCULATION 0

Functional but not perfect, for instance no error handling for erroneous input.