More on Functions

1
More on Functions

• B. Ramamurthy
• Chapter 5

2
Introduction

• 1. Function Prototype
• 2. Function Definition
• 3. Function Call
• 4. Function parameters
• 5. Function Usage
• 6. Function execution trace

3
Function Prototype

• Function prototype specifies the format
  (signature) for calling a function.
• Function prototype is declared at the top of your
  program before the main function.
• It is same as the function header but with a
  semicolon at the end.
• Example Here is the prototype for factoiral
  function
• int factorial (int n)

4
Function Definition

• int factorial (int n)
• int product 1
• for (int j 1 jlt n j)
• product product j
• return product

5
Function Invocation ( or call)

• ..
• int main()
• int n 7
• int x
• x factorial (n)
• x factorial (9)

6
Function Parameter

• This help customize a function.
• Parameters are specified at the header of a
  definition as place holders
• Actual value of the parameters are passed in at
  the time of function invocation.

7
Function Parameters

• Write a function for rectangle code
• Parameterize the function add length and width
  as parameters to the function
• Call/Invoke function with different parameters.

8
Function Execution

• When a function is called control is transferred
  into the function
• Parameters are assigned
• Execution begin at the first statement inside the
  function.
• It continues until the end of the function.
• Then control is transferred back to invoking
  method.

9
Summary

• Functions provide basic construct to modularize
  you solution.
• Practice writing functions.
• Read Chapter 5.