### Function - Void

```//DISPLAY 5.2 void Functions
//Program to convert a Fahrenheit temperature to a Celsius temperature.
#include <iostream>

void initialize_screen( );
//Separates current output from
//the output of the previously run program.

double celsius(double fahrenheit);
//Converts a Fahrenheit temperature
//to a Celsius temperature.

void show_results(double f_degrees, double c_degrees);
//Displays output. Assumes that c_degrees
//Celsius is equivalent to f_degrees Fahrenheit.

int main( )
{
using namespace std;
double f_temperature, c_temperature;

initialize_screen( );
cout << "I will convert a Fahrenheit temperature"
<< " to Celsius.\n"
<< "Enter a temperature in Fahrenheit: ";
cin >> f_temperature;

c_temperature = celsius(f_temperature);

show_results(f_temperature, c_temperature);
return 0;
}

//Definition uses iostream:
void initialize_screen( )
{
using namespace std;
cout << endl;
return;
}
double celsius(double fahrenheit)
{
return ((5.0/9.0)*(fahrenheit - 32));
}
//Definition uses iostream:
void show_results(double f_degrees, double c_degrees)
{
using namespace std;
cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(1);
cout << f_degrees
<< " degrees Fahrenheit is equivalent to\n"
<< c_degrees << " degrees Celsius.\n";
return; // Optional
}
```

### Function - super market

```//DISPLAY 5.11 Program with a Stub
//Determines the retail price of an item according to
//the pricing policies of the Quick-Shop supermarket chain.
#include <iostream>

void introduction( );
//Postcondition: Description of program is written on the screen.

void get_input(double& cost, int& turnover);
//Precondition: User is ready to enter values correctly.
//Postcondition: The value of cost has been set to the
//wholesale cost of one item. The value of turnover has been
//set to the expected number of days until the item is sold.

double price(double cost, int turnover);
//Precondition: cost is the wholesale cost of one item.
//turnover is the expected number of days until sale of the item.
//Returns the retail price of the item.

void give_output(double cost, int turnover, double price);
//Precondition: cost is the wholesale cost of one item; turnover is the
//expected time until sale of the item; price is the retail price of the item.
//Postcondition: The values of cost, turnover, and price have been
//written to the screen.

int main( )
{
double wholesale_cost, retail_price;
int shelf_time;

introduction( );
get_input(wholesale_cost, shelf_time);
retail_price = price(wholesale_cost,shelf_time);
give_output(wholesale_cost, shelf_time, retail_price);

return 0;
}

//Uses iostream:
void introduction( )
{
using namespace std;
cout << "This program determines the retail price for\n"
<< "an item at a Quick-Shop supermarket store.\n";
}
//Uses iostream:
void get_input(double& cost, int& turnover)
{
using namespace std;
cout << "Enter the wholesale cost of item: \$";
cin >> cost;
cout << "Enter the expected number of days until sold: ";
cin >> turnover;
}

//Uses iostream:
void give_output(double cost, int turnover, double price)
{
using namespace std;
cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(2);
cout << "Wholesale cost = \$" << cost << endl
<< "Expected time until sold = "
<< turnover << " days" << endl
<< "Retail price= \$" << price << endl;
}

//This is only a stub:
double price(double cost, int turnover)
{
return(9.99); //Not correct, but good enough for some testing.
}

```

This topic: SCMP118/Fall2016 > WebHome > CodeCh5
Topic revision: r1 - 2016-09-26 - JimSkon

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