Errors and Debugging in Python

☞ Error : When our application suddenly freezes for no apparent reason, it is known as an error.

☞ Debugging : The process of finding errors in a program is known as debugging.

☞ Three types of errors :

1. Syntax Error :
   It is an error in the syntax.
   Eg : Incorrect indentation, Misspelling a keyword, leaving semi-colon(;), comma(,) etc.
   
   print 'hello' #SyntaxError : missing parenthesis
   L=[4; 7; 9] #SyntaxError : invalid syntax
2. Logical Error/bug/semantic error :
   It does not stop execution but the program behaves incorrectly and produces wrong output.
   Eg : Using the wrong variable name, giving wrong operator precedence.
   
   #Finding average of two numbers
   a = 15
   b = 17
   c = a + b / 2 #logical error-operator precedence, it must be (a+b)/2
   print(c)
   
3. Run-time Error :
   It usually results in abnormal program termination during execution.
   Eg : division by zero, trying to access file or elements that doesn’t exist.
   
   a = 15
   c = b / 0 #ZeroDivisionError : division by zero
   print(c)