For for Control Structures

Fuel Warning

```//Illustrates the importance of using braces in if-else statements.
#include <iostream>
using namespace std;
int main( )
{

cout << "Enter fuel gauge reading: ";

cout << "First with braces:\n";
{
cout << "Fuel very low. Caution!\n";
}
else
{
cout << "Fuel over 3/4. Dont stop now!\n";
}

cout << "Now without braces:\n";
cout << "Fuel very low. Caution!\n";
else
cout << "Fuel over 3/4. Don't stop now!\n";

return 0;
}
```

Multiway if-else Statement - Program to compute state income tax.

```//DISPLAY 3.5 Multiway if-else Statement
//Program to compute state income tax.
#include <iostream>
using namespace std;

//This program outputs the amount of state income tax due computed
//as follows: no tax on income up to \$15,000; 5% on income between
//\$15,001 and \$25,000; 10% on income over \$25,000.

int main( )
{
int net_income;
double tax_bill;
double five_percent_tax, ten_percent_tax;

cout << "Enter net income (rounded to whole dollars) \$";
cin >> net_income;

if (net_income <= 15000)
tax_bill = 0;
else if ((net_income > 15000) && (net_income <= 25000))
//5% of amount over \$15,000
taxc_bill = (0.05*(net_income - 15000));
else //net_income > \$25,000
{
//five_percent_tax = 5% of income from \$15,000 to \$25,000.
five_percent_tax = 0.05*10000;
//ten_percent_tax = 10% of income over \$25,000.
ten_percent_tax = 0.10*(net_income - 25000);
tax_bill = (five_percent_tax + ten_percent_tax);
}

cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(2);
cout << "Net income = \$" << net_income << endl
<< "Tax bill = \$" << tax_bill << endl;

return 0;
}
```

A switch Statement

```DISPLAY 3.6 A switch Statement
//Program to illustrate the switch statement.
#include <iostream>
using namespace std;

int main( )
{

{
case 'A':
cout << "Excellent. "
<< "You need not take the final.\n";
break;
case 'B':
cout << "Very good. ";
break;
case 'C':
cout << "Passing.\n";
break;
case 'D':
case 'F':
cout << "Not good. "
<< "Go study.\n";
break;
default:
cout << "That is not a possible grade.\n";
}

cout << "End of program.\n";
return 0;
}
```

```//DISPLAY 3.7 A Menu
//Program to give out homework assignment information.
#include <iostream>
using namespace std;

int main( )
{
int choice;

do
{
cout << endl
<< "Choose 1 to see the next homework assignment.\n"
<< "Choose 3 for assignment hints.\n"
<< "Choose 4 to exit this program.\n"
<< "Enter your choice and press Return: ";
cin >> choice;

switch (choice)
{
case 1:
//code to display the next assignment on screen would go here.
break;
case 2:
//code to ask for a student number and give the corresponding
break;
case 3:
//code to display a hint for the current assignment would go
//here.
break;
case 4:
cout << "End of Program.\n";
break;
default:
cout << "Not a valid choice.\n"
<< "Choose again.\n";
}
}while (choice != 4);

return 0;
}

```

Block with a Local Variable

```//DISPLAY 3.8 Block with a Local Variable
//Program to compute bill for either a wholesale or a retail purchase.
#include <iostream>
using namespace std;
const double TAX_RATE = 0.05; //5% sales tax.

int main( )
{
char sale_type;
int number;
double price, total;

cout << "Enter price \$";
cin >> price;
cout << "Enter number purchased: ";
cin >> number;
cout << "Type W if this is a wholesale purchase.\n"
<< "Type R if this is a retail purchase.\n"
<< "Then press Return.\n";
cin >> sale_type;

if ((sale_type = = 'W') || (sale_type = = 'w'))
{
total = price * number;
}
else if ((sale_type = = 'R') || (sale_type = = 'r'))
{
double subtotal;
subtotal = price * number;
total = subtotal + subtotal * TAX_RATE;
}
else
{
cout << "Error in input.\n";
}
cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(2);
cout << number << " items at \$" << price << endl;
cout << "Total Bill = \$" << total;
if ((sale_type = = 'R') || (sale_type = = 'r'))
cout << " including sales tax.\n";

return 0;
}

```

The Increment Operator as an Expression

```//DISPLAY 3.10 The Increment Operator as an Expression
//Calorie-counting program.
#include <iostream>
using namespace std;

int main( )
{
int number_of_items, count,
calories_for_item, total_calories;

cout << "How many items did you eat today? ";
cin >> number_of_items;

total_calories = 0;
count = 1;
cout << "Enter the number of calories in each of the\n"
<< number_of_items << " items eaten:\n";

while (count++ <= number_of_items)
{
cin >> calories_for_item;
total_calories = total_calories
+ calories_for_item;
}

cout << "Total calories eaten today = "
<< total_calories << endl;
return 0;
}

```

A break Statement in a Loop

```//DISPLAY 3.14 A break Statement in a Loop
//Sums a list of ten negative numbers.
#include <iostream>
using namespace std;

int main( )
{
int number, sum = 0, count = 0;
cout << "Enter 10 negative numbers:\n";

while (++count <= 10)
{
cin >> number;

if (number >= 0)
{
cout << "ERROR: positive number"
<< " or zero was entered as the\n"
<< count << "th number! Input ends "
<< "with the " << count << "th number.\n"
<< count << "th number was not added in.\n";
break;
}

sum = sum + number;
}

cout << sum << " is the sum of the first "
<< (count - 1) << " numbers.\n";

return 0;
}
```

Explicitly Nested Loops

```//DISPLAY 3.15 Explicitly Nested Loops
//Determines the total number of green-necked vulture eggs
//counted by all conservationists in the conservation district.
#include <iostream>
using namespace std;

void instructions ();

int main()
{
cout << "This program tallies conservationist reports\n"
<< "on the green-necked vulture.\n"
<< "Each conservationist's report consists of\n"
<< "a list of numbers. Each number is the count of\n"
<< "the eggs observed in one๎
<< "green-necked vulture nest.\n"
<< "This program then tallies
<< "the total number of eggs.\n";

int number_of_reports;
cout << "How many conservationist reports are there? ";
cin >> number_of_reports;

int grand_total = 0, subtotal, count;
for (count = 1; count <= number_of_reports; count++)
{
cout << endl << "Enter the report of "
<< "conservationist number " << count << endl;
cout << "Enter the number of eggs in each nest.\n"
<< "Place a negative integer at the end of your list.\n๎;๎
subtotal = 0;
int next;
cin >> next;
while (next >=0)
{
subtotal = subtotal + next;
cin >> next;
}
cout << "Total egg count for conservationist "
<< " number " << count << " is "
<< subtotal << endl;
grand_total = grand_total + subtotal;
}
cout << endl << "Total egg count for all reports = "
<< grand_total << endl;

return 0;
}
```

This topic: SCMP118/Fall2016 > WebHome > CodeControl
Topic revision: r2 - 2017-09-20 - JimSkon

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