Using Functions

USING FUNCTIONS

In the second chapter we have discussed that when we execute a C program, the operating system calls the main() function of the program which marks the entry point for the execution. When the program is executed, the main () returns some value to the operating system.

Any function (including main()) can be compared to a black box that takes in input, processes it, and then produces the result. However, we may also have a function that does not take any inputs at all, or the one that does not return anything at all.

While using functions we will be using the following terminologies:

• A function f that uses another function g is known as the calling function and g is known as the called function.

• The inputs that a function takes are known as arguments/ parameters.

• When a called function returns some result back to the calling function, it is said to return that result.

• The calling function may or may not pass parameters to the called function. If the called function accepts arguments, the calling function will pass parameters, else it will not do so.

• Function declaration is a declaration statement that identifies a function with its name, a list of arguments that it accepts, and the type of data it returns.

• Function definition consists of a function header that identifies the function, followed by the body of the function containing the executable code for that function.