created 07/29/99

# Chapter 13 Programming Exercises

## Exercise 1 --- Internet Delicatessen

Sam and Ella's Delicatessen wants you to write a program to take orders from the Internet. Your program asks for the item, its price, and if overnight shipping is wanted. Regular shipping for items under \$10 is \$2.00; for items \$10 or more shipping is \$3.00. For overnight delivery add \$5.00.

```Enter the item:
Tuna Salad
Enter the price:
450
Overnight delivery (0==no, 1==yes)
1

Invoice:
Tuna Salad    4.50
shipping      7.00
total         11.50
```

(Use our ordinary IO methods. A real Internet order form would use different I/O methods, but ignore this.)

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## Exercise 2 --- Steam Engine Efficiency

The maximum possible efficiency of a steam engine depends on the temperature of the steam in the boiler and the temperature of the outside air:

```efficiency = 1 - Tair / Tsteam
```

where `Tair ` is the air temperature and `Tsteam ` is the steam temperature. The temperatures are give in degrees above absolute zero. Normal air temperature is about 300oK. Boiling is 373oK. Write a program that asks the user for the air temperature and the steam temperature and writes out the maximum possible efficiency of a steam engine. However, if the steam temperature is less than 373oK there is no steam, so the efficiency is zero.

Use integer or floating point input, but do the calculations in floating point.

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## Exercise 3 --- Microwave Oven

A microwave oven manufacturer recommends that when heating two items, add 50% to the heating time, and when heating three items double the heating time. Heating more than three items at once is not recommended.

Write a program that asks the user for the number of items and the single-item heating time. The program then writes out the recommended heating time.

Hint: do this with four successive single-branch if statements each of which tests for one of the four cases: 1 item, 2 items, 3 items, more than three items. Look at the sports car purchase program in the chapter to see how to do this, if you are stuck.

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## Exercise 4 --- Fantasy Game

In a new role-playing fantasy game players must design their character by picking a point value for each of three characteristics:

• Strength, from 1 to 10
• Health, from 1 to 10
• Luck, from 1 to 10

Write a program that asks for a name for the character and asks for the point value of for each of the three characteristics. However, the total points must be less than 15. If the total exceeds 15, then 5 points are assigned to each characteristic

```Welcome to Yertle's Quest
Enter the name of your character:
Chortle
Enter strength (1-10):
8
Enter health (1-10):
4
Enter luck (1-10):
6

You have give your character too many points!  Default values have been assigned:
Chortle, strength: 5, health: 5, luck: 5
```

(This user interface could get much more complicated. You might want to implement some of your own ideas.)

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