Python Programming (Basics)- Debugging & Types of errors

Debugging and Types of errors in Python


Errors occurring in programming are called as bugs.The process of tracking this bugs is called as debugging. There are three types of errors that can occur while coding : Syntax Error, Runtime Error and Semantic Error.

Syntax Error

The syntax is a defined structure or set of rules while writing a program. If someone fails to maintain correct syntax ,then it may lead to Syntax Error.

Author : ITVoyagers (

Date : 14th June 2019

Description : Program to explain Syntax Error
>>> a=1+2
>>> a
>>> 1+2=a
SyntaxError: can't assign to operator
In above example a=1+2 is correct syntax where as 1+2=a is incorrect as in first case value is assigned to variable and in second case we are trying to assign a variable to value.

Runtime Error

This type of error does not appear until program is executed. In this,program is executed successfully without syntax or logical error and this type of error occurs at runtime i.e. while accepting values from user. Runtime errors are also called as exceptions or interruptions in program.
Author : ITVoyagers (

Date : 14th June 2019

Description : Program to explain Runtime Error
#Program to explain Runtime Error
d=input("enter a number")

enter a number5
Traceback (most recent call last):
  File "C:/Python34/runtime", line 5, in 
TypeError: unsupported operand type(s) for +: 'int' and 'str'
In above example program is executed successfully and idle displays the output to enter a number,after entering a number input function sends the value to variable d but without converting to int so Runtime error occurs.

Semantic Error

In this program will be executed without any error on prompt but will not give desired output.Such type of error is called Semantic error. Semantic errors are also called as logical errors. It is difficult to track such errors as it requires to go backward to look for output and find errors causing incorrect output.
Author : ITVoyagers (

Date : 14th June 2019

Description : Program to explain Semantic Error
#Program to find sum of two digits
num1=int(input("Enter first number"))
num2=int(input("Enter second number"))
add = num1 - num2
print("sum of two nums is ", add )
Enter first number200
Enter second number57
sum of two nums is  143
In above example sum of two numbers is expected also program is executed without syntax of runtime error, still desired output is not achieved due to logical error. Instead of “+” symbol “-” is used.

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