Class 12 Computer Science Chapter 13 Notes

• Important Class 12 Computer Science Chapter 13 Notes for Intermediate part-II students.
• Describe Unstructured and Structured Programming ? Define Function and differentiate between Unstructured and Structured Programming: Overview : The idea of modular programming is the result of inspiration from the hardware manufacturing where replicable components of different items are available. If a component of an item gets out of order, it is replaced with a newer one. Many different components from different manufacturers can be combined together to form a hardware device such as computers, cars, and washing machines. Functions : Functions are the building blocks of C programs. They encapsulate pieces of code to perform specific operations. Functions allow us to accomplish the similar kinds of tasks over and over again without being forced to keep adding the same code into the program. Functions perform tasks that may need to be repeated many times. Unstructured Programming : When the whole program logic is contained in a single main function, the style of writing programs is known as unstructured programming. Structured Programming : It is a modular way of writing programs. The whole program logic is divided into number of smaller modules or functions. The main function calls these functions where they are needed. A function is a self-contained piece of code with a specific purpose. Difference between Unstructured and Structured Programming : In Unstructured Programming, the entire logic of the program is implemented in a single module (function), which causes the program error prone, difficult to understand, modify and debug. Whereas in Structured Programming, the entire logic of the program is divided into number of smaller modules, where each module (piece of code) implements a different functionality. 
• Describe Importance / Benefits of Use of Functions.
• Explain the TWO Types of Functions.
• Explain the procedure of writing a Function in C.
• Explain the Function Prototype in C.
• Explain the Function Call in C: Answer : Function Call In C : Function call is a mechanism that is used to invoke a function to perform a specific task. A function call can be invoked at any point in the program. In C the function name, the arguments required and the statement terminator ( ; ) are specified to invoke a function call. When function call statement is executed, it transfers control to the function that is called. The memory is allocated to variables declared in the function and then the statements in the function body are executed. After the last statement in the function is executed, control returns to the calling function. 
• Explain Local Variables in C, their Life Time, Memory Allocation / De-allocation and The Scope of a Local Variable with an example program.
• Explain Global Variables in C, their Life Time, Memory Allocation / De-allocation and The Scope of a Local Variable with an example program.
• Explain Functions Without Arguments with an example program.
• Explain Functions that Return a Value and Accept Arguments / Parameters with example program(s): Functions that Return a Value and Accept Arguments / Parameters : We may need a function that could return a value and arguments could be passed to it. We have seen a number of such built-in library functions e.g., sqrt( ), toupper( ), tolower( ) etc. Let’s consider the general form of function header : return_type FunctionName (parameter_list) The return_type specifies the data type of the value that the function returns. Parameter_list is a comma separated list which specifies the data type and the name of each parameter in the list.