#include

#include

using namespace std;

int main$()$

$\{$

const double PI $=3\mathrm{.}14159$;

int choice; $//$ User's shape choice

double radius, $//$ Circle radius

length, $//$ Rectangle length

width, $//$ Rectangle width

base, $//$ Triangle base

height, $//$ Triangle height

area; $//$ Area of the selected shape

$//$ Configure cout so real numbers are output in fixed notation with $2$ digits

$//$ following the decimal point.

cout $<<$ fixed $<<$ setprecision$(2)<<$ endl;

CSE$100$ Homework $320$ Points

$1.(10$ pts$)$ Study the program in the source code file named h$3.$cpp$.$ Create a text file named h$1$a$.$txt

specifying within it the program output when it is run and the program input is $14.$

$2.(10$ pts$)$ Modify h$3.$cpp $($storing the code for the new program in h$3-1.$cpp$)$ to insert a new user

choice in between $3$ Calculate the area of a triangle and $4$ Quit. The new choice shall output a prompt

asking the user to enter the base of a parallelogram and shall read the base from the keyboard. Next, it

will output a prompt asking the user to input the height of the parallelogram and shall read the height

from the keyboard. Next, the program shall calculate the area of the parallelogram and shall output the

area. All real numbers shall be output with two digits following the decimal point. Every output line shall

be terminated with a newline.

When you have completed the assignment, submit h$1$a$.$txt and h$3-1.$cpp to Gradescope for grading.$//$ Display selections and request user input

cout $<<$ "Geometry Calculator

$"$;

cout $<<"1.$ Calculate the area of a Circle

$"$;

cout $<<"2.$ Calculate the area of a Rectangle

$"$;

cout $<<"3.$ Calculate the area of a Triangle

$"$;

cout $<<"4.$ Quit

$"$;

cout $<<$ "Enter your choice $(1-4)$:

$"$;

cin $>>$ choice;

$//$ Calculate and display the area of the selected shape

switch $($choice$)$

$\{$

case $1$: $//$ Area of a circle

cout $<<"$

Enter the circle's radius:

$"$;

cin $>>$ radius;

if $($radius $<0)$

cout $<<"$

The radius can not be less than zero.

$"$;

else

$\{$ area $=$ PI $*$ radius $*$ radius;

cout $<<"$

The area is $"<<$ area $<<$ endl;

break;

$\}$

case $2$: $//$ Area of a rectangle

cout $<<"$

Enter the rectangle's length:

$"$;

cin $>>$ length;

cout $<<$ "Enter the rectangle's width:

$"$;

cin $>>$ width;

if $($length $<0||$ width $<0)$

cout $<<"$

Only enter positive values for length and width.

$"$;

else

$\{$ area $=$ length $*$ width;

cout $<<"$

The area is $"<<$ area $<<$ endl;

$\}$

break;

case $3$: $//$ Area of a triangle

cout $<<$ "Enter the length of the base:

$"$;

cin $>>$ base;

cout $<<$ "Enter the triangle's height:

$"$;

cin $>>$ height;

if $($base $<0||$ height $<0)$

cout $<<"$

Only enter positive values for base and height.

$"$;

else

$\{$ area $=$ base $*$ height $*0\mathrm{.}5$;

cout $<<"$

The area is $"<<$ area $<<$ endl;

$\}$

break;

case $4$: cout $<<"$

Bye!

$"$;

break;

default: cout $<<"$

You may only enter $1,2,3,$ or $4.$

$"$;

$\}$

return $0$;

$\}$