Chapter 15, Problem 15.5E

Write a C++ program that prompts the user for the radius of a circle, then calls inline function circleArea to calculate the area of that circle.

Program Plan Intro

Program Plan:

An inline function circleArea() is defines to calculate the area of circle.

Variable radiusValue is used to save the value of radius entered by user.

Program Description: Purpose of the program is to define an inline function circleArea() to calculate the area of circle. The formula used to calculate area of circle is =II×r².

Explanation of Solution

Program: Following is C++ Program that prompt user to enter radius of circle calculates area of circle by calling inline function circleArea.

//include necessary header files
#include <iostream>
usingnamespace std; 
/*The inline function circleArea is defined which takes input argument 
radius and calculates the area of circle */
inlinedoublecircleArea( constdouble radius ) 
{ 
// formula for Radius = pi * ( radius ^ 2 ) 
return (3.14) * radius * radius; 
} 
//start of main method 
intmain()
{

// Declare variables to store the value of radius 
doubleradiusValue; 

// Prompt user to enter the value of radius 
cout<<"\nEnter the radius of your circle: "; 

// read the value of radius from user 
cin>>radiusValue; 

// calculate the area of circle and finally display the result 
cout<<"Area of circle with radius "<<radiusValue<<
" is "<<circleArea( radiusValue ) <<endl; 
}//end of main 

Explanation:

The given C++ program calculates the area of circle using inline function.

• Import the essential header and initialize the main() function.
• Define inline function circleArea with radius as argument.
• Declare variable radiusValue for radius of the circle.
• Formula used to calculate the area of circle is =?×r².
• Prompt user to enter the radius of circle.
• Calculate and finally display the output.

Sample Output: