c++ program to find area of circle :

c++ program to find area of circle using functions...  

This Cpp Tutorial covers the concept of
if else if statement
for loop
function with parameter and return value
Cpp tutorial to calculate area of circle
User enter radius or diameter of circle.
Program should have two functions one which takes radius as parameter and second takes diameter as parameter.
If user enters wrong option then tell users its valid selection and chose again the right option. ‪#‎include‬ <iostream> ‪#‎define‬ PI 3.14159
using namespace std;
float AreaOfCircle(float radius);
float AreaWithDiameter(float diameter);
int main()
{
float radius,diameter,circleArea;
char choice='0';
cout<<"\n\t\t\tFind Area Of Circle:"<<endl;
for(;choice!='1'&&choice!='2'wink emoticon
{
cout<<"\nEnter 1 to Enter Radius OR
2 to Enter Diameter: ";
cin>>choice;
if(choice!='1'&&choice!='2')
cout<<"\n\t\tEnter a VALID Option ";
}
if(choice=='1')
{
cout <<"\n\t\tEnter Radius To Find Area: ";
cin>>radius;
circleArea=AreaOfCircle(radius);
}
else if(choice=='2')
{
cout <<"\n\t\tEnter Diameter To Find Area: ";
cin>>diameter;
circleArea=AreaWithDiameter(diameter);
}
cout<<"\n\n\t\tArea of Circle is:->> "<<circleArea<<endl;
return 0;
}
float AreaOfCircle(float radius)
{
return (PI*(radius*radius));
}
float AreaWithDiameter(float diameter)
{
return (AreaOfCircle(diameter/2));
}