Chapter $4$: Programming Project $2$

Unlimited tries

Write a program that displays the following menu. The

symbols show where newline characters $("$

$")$ should be displayed:

Geometry Calculator

$1.$ Calculate the Area of a Circle

$2.$ Calculate the Area of a Rectangle

$3.$ Calculate the Area of a Triangle

$4.$ Quit

Enter your choice $(1-4)$:

If the user enters $1$: The program should print the following string as a prompt:

$"$

Enter the circle's radius: $"$

The program should then read the radius of the circle as input and then calculate the circle's area using the following formula:

Area $=\backslash$pi r$2$

In your calculation, use $3\mathrm{.}14159$ for $\backslash$pi and the radius of the circle for r$.$

The program should then print the string $"$

The area is $",$ followed by the area, followed by a newline.

If the user enters $2$: The program should print the following string as a prompt:

$"$

Enter the rectangle's length: $"$

The program should read the length as input and then print the following string as a prompt:

"Enter the rectangle's width: $"$

The program should read the width as input and then calculate the rectangle's area using the following formula:

Area $=$ length $\backslash$times width

The program should then print the string $"$

The area is $",$ followed by the area, followed by a newline.

If the user enters $3$: The program should print the following string as a prompt:

"Enter the length of the base: $"$

The program should read the base as input and then print the following string as a prompt:

"Enter the triangle's height: $"$

The program should read the height as input and then calculate the triangle's area using the following formula:

Area $=$ base $\backslash$times height $\backslash$times $0\mathrm{.}5$

The program should then print the string $"$

The area is $",$ followed by the area, followed by a newline.

If the user enters $4$: The program should print the string "Program ending.

$",$ and then end.

Input Validation:

The only valid menu choices the user can make are $1,2,3,$ or $4.$ If the user makes a menu choice other than one of these numbers, the program should print the following strings and then end:

"The valid choices are $1$ through $4.$ Run the

$"$

"program again and select one of those.

$"$

If the user enters a negative number for the circle's radius, print the following string, and then end:

$"$

The radius can not be less than zero.

$"$

If the user enters a negative number for the rectangle's length OR width, print the following string, and then end:

$"$

Only enter positive values for length and width.

$"$

If the user enters a negative number for the triangle's base OR height, print the following string, and then end:

$"$

Only enter positive values for base and height.

$"$

Sample Run

Geometry Calculator

$1.$ Calculate the area of a Circle

$2.$ Calculate the area of a Rectangle

$3.$ Calculate the area of a Triangle

$4.$ Quit

Enter your choice $(1-4)$: $1$

Enter the circle's radius: $1$

The area is $3\mathrm{.}14159$

Sample Run

Geometry Calculator

$1.$ Calculate the area of a Circle

$2.$ Calculate the area of a Rectangle

$3.$ Calculate the area of a Triangle

$4.$ Quit

Enter your choice $(1-4)$: $2$

Enter the rectangle's length: $10$

Enter the rectangle's width: $20$

The area is $200$