Program testing and debugging:

Program testing is the method of checking program, to verify that it satisfies its needs and to detect errors. These errors can be of any type-Syntax errors, Logical errors, Run-time errors and Latent errors. Testing include essential steps to detect all possible errors in the program. This can be completed either at a module level called as unit testing or at program level called as integration testing. 

Debugging is a methodical process of finding and decreasing the number of bugs in a computer program making it behave as expected. One easy way to find the location of the error is to use print statement to show the values of the variables. Once the location of the error is found, the error is corrected and debugging statement may be separate.