1. Function Basics

2. Function Basics
The basic concept of a function is to break down the larger programming project into smaller, more specialized blocks of code.
int main() {     display_greetings();     gather_data();     calculate();     output();     sign_off();     return 0; }

3. Motivation
Functions will help you to organize your code into smaller units or modules that provide a sort of outline for the program.
Functions allow the programming of very large projects to be done by teams of programmers.
You will occasionally find yourself using a module of code more than once.
Some units of code are so useful that you can carry them from project to project.

4. Function Format
return_type function_name ( formal_parameter_list ) {     local variable declarations     statements     return value_of_return_type; }

5. return_type function_name ( formal_parameter_list ) {     local variable declarations     statements     return value_of_return_type; }
int main ( )      {     char quit = ‘y’; do {
cout << “Loop again? ”;
cin >> quit;     } while (quit != ‘n’);
    return 0; }

6. return_type function_name ( formal_parameter_list ) {     local variable declarations     statements     return value_of_return_type; }
int main ( )      {     char quit = ‘y’; do {
cout << “Loop again? ”;
cin >> quit;     } while (quit != ‘n’);
    return 0; }

7. return_type function_name ( formal_parameter_list ) {     local variable declarations     statements     return value_of_return_type; }
int main ( )      {     char quit = ‘y’; do {
cout << “Loop again? ”;
cin >> quit;     } while (quit != ‘n’);
    return 0; }

8. return_type function_name ( formal_parameter_list ) {     local variable declarations     statements     return value_of_return_type; }
int main ( )      {     char quit = ‘y’; do {
cout << “Loop again? ”;
cin >> quit;     } while (quit != ‘n’);
    return 0; }

9. return_type function_name ( formal_parameter_list ) {     local variable declarations     statements     return value_of_return_type; }
int main ( )      {     char quit = ‘y’; do {
cout << “Loop again? ”;
cin >> quit;     } while (quit != ‘n’);
    return 0; }

10. return_type function_name ( formal_parameter_list ) {     local variable declarations     statements     return value_of_return_type; }
int main ( )      {     char quit = ‘y’; do {
cout << “Loop again? ”;
cin >> quit;     } while (quit != ‘n’);
    return 0; }

11. return_type function_name ( formal_parameter_list ) {     local variable declarations     statements     return value_of_return_type; }
int main ( )      {     char quit = ‘y’; do {
cout << “Loop again? ”;
cin >> quit;     } while (quit != ‘n’);
    return 0; }

12. #include <iostream> using namespace std; void greetings( ); int main( ) {     greetings( );     return 0; } void greetings( ) {     cout<<"Hello there, welcome to my world."<<endl;     return; }

13. #include <iostream> using namespace std; void greetings( ); int main( ) {     greetings( );     return 0; } void greetings( ) {     cout<<"Hello there, welcome to my world."<<endl;     return; }

14. #include <iostream> using namespace std; void greetings( ); int main( ) {     greetings( );     return 0; } void greetings( ) {     cout << "Hello there, welcome to my world." << endl;     return; }

15. #include <iostream> using namespace std; void greetings( ); int main( ) {     greetings( );     return 0; } void greetings( ) {     cout << "Hello there, welcome to my world." << endl;     return; }

16. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

17. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

18. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

19. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

20. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

21. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

22. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

23. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

24. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

25. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

26. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

27. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

28. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

29. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

30. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

31. #include <iostream> using namespace std; void display_number (int a_number); int main() {     int bob = 5;     display_number (bob);     return 0; } void display_number (int a_number) {     cout << a_number;     return; }

32. #include <iostream> using namespace std; int get_number ( ); int main() {     int bob;    bob = get_number ( );     return 0; } int get_number() {     int value_to_get;     cout << "Enter an integer: ";     cin >> value_to_get;     return value_to_get; }

33. #include <iostream> using namespace std; int get_number ( ); int main() {     int bob;    bob = get_number ( );     return 0; } int get_number() {     int value_to_get;     cout << "Enter an integer: ";     cin >> value_to_get;     return value_to_get; }

34. #include <iostream> using namespace std; int get_number ( ); int main() {     int bob;    bob = get_number ( );     return 0; } int get_number() {     int value_to_get;     cout << "Enter an integer: ";     cin >> value_to_get;     return value_to_get; }

35. #include <iostream> using namespace std; int get_number ( ); int main() {     int bob;    bob = get_number ( );     return 0; } int get_number() {     int value_to_get;     cout << "Enter an integer: ";     cin >> value_to_get;     return value_to_get; }

36. #include <iostream> using namespace std; int get_number ( ); int main() {     int bob;    bob = get_number ( );     return 0; } int get_number() {     int value_to_get;     cout << "Enter an integer: ";     cin >> value_to_get;     return value_to_get; }

37. #include <iostream> using namespace std; int get_number ( ); int main() {     int bob;    bob = get_number ( );     return 0; } int get_number() {     int value_to_get;     cout << "Enter an integer: ";     cin >> value_to_get;     return value_to_get; }

38. #include <iostream> using namespace std; int get_number ( ); int main() {     int bob;    bob = get_number ( );     return 0; } int get_number() {     int value_to_get;     cout << "Enter an integer: ";     cin >> value_to_get;     return value_to_get; }

39. #include <iostream> using namespace std; int get_number ( ); int main() {     int bob;    bob = get_number ( );     return 0; } int get_number() {     int value_to_get;     cout << "Enter an integer: ";     cin >> value_to_get;     return value_to_get; }

40. #include <iostream> using namespace std; int get_number ( ); int main() {     int bob;    bob = get_number ( );     return 0; } int get_number() {     int value_to_get;     cout << "Enter an integer: ";     cin >> value_to_get;     return value_to_get; }

41. #include <iostream> using namespace std; int get_number ( ); int main() {     int bob;    bob = get_number ( );     return 0; } int get_number() {     int value_to_get;     cout << "Enter an integer: ";     cin >> value_to_get;     return value_to_get; }

42. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

43. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

44. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

45. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

46. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

47. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

48. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

49. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

50. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

51. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

52. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

53. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

54. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

55. void greetings(); int get_number (); float average (const float val1, const float val2); int main() {     float bob, sue, the_average;     greetings();     bob = get_number();     sue = get_number();     the_average = average (bob, sue);     return 0; } float average (const float val1, const float val2) {     float sum, ave;     sum = val1 + val2;     ave = sum / 2;     return ave; }

56. float average (const float val1, const float val2); int main() {     float the_average;     the_average = average (45, 3.1);     return 0; } float average (const float val1, const float val2) {     return (val1 + val2) / 2; }

57. float average (const float val1, const float val2); int main() {     float the_average;     the_average = average (45, 3.1);     return 0; } float average (const float val1, const float val2) {     return (val1 + val2) / 2; }

58. float average (const float val1, const float val2); int main() {     float the_average;     the_average = average (45, 3.1);     return 0; } float average (const float val1, const float val2) {     return (val1 + val2) / 2; }

59. #include <iostream> using namespace std; const float PI = 3
#include <iostream> using namespace std; const float PI = ; float cyl_vol (const float, const float); int main() {     cout << cyl_vol(3,5);     cout << radius;     return 0; } float cyl_vol (const float radius, const float height) {     return PI*radius*radius*height; }

60. #include <iostream> using namespace std; const float PI = 3
#include <iostream> using namespace std; const float PI = ; float cyl_vol (const float, const float); int main() {     cout << cyl_vol(3,5);     cout << radius;     return 0; } float cyl_vol (const float radius, const float height) {     return PI*radius*radius*height; }

61. #include <iostream> using namespace std; const float PI = 3
#include <iostream> using namespace std; const float PI = ; float cyl_vol (const float, const float); int main() {     cout << cyl_vol(3,5);     cout << radius;     return 0; } float cyl_vol (const float radius, const float height) {     return PI*radius*radius*height; }

62. void blanklines (const short num_lines);
int main() {
blanklines(5);
return 0;
} void blanklines (const short num_lines) {     for(short i = 1; i <= num_lines; i++)         cout<<endl;     return; }

63. End of Session