1. Programming Fundamental
Instructor Name: Muhammad Safyan
Lecture-11

2. Lecture outline
Unconditional Statement (goto)
Function

3. Unconditional Branch of Execution
goto
Unconditional Branch of Execution

4. int i=0;
while (i<=10) {
goto a;
cout<<"GCU"<<endl;
i=i+1; }
a: cout<<"CSD";

5. Minimize the use of break
Advice
Minimize the use of break
Minimize the use of continue
Never use goto

6. What have we done till now …
Sequential Statements
Decisions
if , if else , switch
Loops
while , do while , for

7. Functions

8. Guide lines for structured programming
Modular
Single entry - single exit

9. Laboratory Stool

10. Constructing a laboratory Stool

11. Constructing a laboratory Stool
Task: Making a stool
Subtask:
Make a seat
Make legs for the stool
Assemble them

12. What we will study today …
What are functions?
How are they declared ?
How are they defined ?
What values are passed to functions ?
What values do functions return ?

13. Function(Objective)
Function: A piece of code that perform a specific task
Divide the Task into sub-Tasks
Divide and conquer approach
Better Understanding
Information Hiding
Reusability

14. Function Steps involve in functions: Declare a function
Define a function
Call a function

15. Declaration of fuction
void function-name( ) ;
main ( ) { : }

16. Define a Function
void function-name( ) { declarations and statements }

17. call a Function
function-name( );

18. // Function Declaration
void pak();
void india();
main() {
cout<<" im in main"<<endl;
// Call Function
pak();
india();
getch(); }
// Function Definition
void pak()
cout<<" i am in pakistan"<<endl;;
void india()
cout<<" i am in india";

19. Function(in Detail) Two types of functions:
Functions that do not return a value
Functions that return a value

20. Function
return-value-type function-name( argument-list ) { declarations and statements }

21. Declaration of Function
return-value-type function-name( argument--type-list) ;
main ( ) { : }

22. Example int function-name ( int , int , double ) ; void main ( ) { ….}

23. Definition of Function
int function-name ( int i ,int k, double j ) { … }

24. Return Type of Function
Declaration
int square ( int ) ;
Definition
int square ( int i ) {
return ( i * i ) ; }

25. Function Call
int x ;
x = square ( i ) ;

26. Example: Function to calculate integer power ( Xn )
double raiseToPow ( double x , int power ) {
double result ;
int i ;
result = 1.0 ;
for ( i = 1 ; i <= power ; i ++ ) // braces first
result * = x ; // result = result *x }
return ( result ) ;

27. Code to Call the raisetopow Function
include < iostream.h >
void main ( ) {
double x ;
int i ;
cout << “ Please enter the number “ ;
cin >> x ;
cout << “ Please enter the integer power that you want this number raised to “ ;
cin >> i ;
cout << x << “ raise to power “ << i << “is equal to “ << raiseToPow ( x , i ) ; }

28. Calling function
Called function

29. Area of the Ring
Area of Outer Circle
= Area of the Ring

30. Calculating ringArea without using Function
main ( ) { :
ringArea = ( * rad1 * rad1 ) – ( * rad2 * rad2 ) ; }

31. Example: Function to calculate the area of a circle
(with Return Value)

32. Example: Function to calculate the area of a circle
(Without Return a value)