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Simulating a Bouncing Ball Using a while Loop
Suppose that when a ball is dropped, it bounces from the pavement to a
height
one half of its previous height. Assume that the double variable
height
contains the height of the ball in meters and that the user has input
its
initial value. Write a while loop that simulates the bouncing
ball.
Each iteration of the loop should calculate and display the height of
the
ball.
1. Stop the loop when the height is less than 0.1 meters.
% cat bounce1.cpp
#include<iostream>
using namespace std;
#include<cmath>
int main()
{
double height;
cout << "Enter the initial height of the ball: ";
cin >> height;
while(height > 0.1)
{
height = height / 2.0;
cout << height << endl;
}
return 0;
}
% g++ bounce1.cpp
% a.out
Enter the initial height of the ball: 32.0
16
8
4
2
1
0.5
0.25
0.125
0.0625
2. Stop the ball when the absolute value of the difference in the
height
between two successive iterations is less than 0.1 meters. You
will
need variables difference, old_height and new_height.
% cat bounce2.cpp
#include<iostream>
using namespace std;
#include<cmath>
int main()
{
double old_height, new_height, difference;
cout << "Enter the initial height of the ball: ";
cin >> old_height;
difference = 1.0; // initialization
while(difference > 0.1)
{
new_height = old_height / 2.0;
cout << new_height << endl;
difference = fabs(new_height - old_height);
old_height = new_height;
}
return 0;
}
cswanson@mega (~/spring06) % g++ bounce2.cpp
cswanson@mega (~/spring06) % a.out
Enter the initial height of the ball: 100.0
50
25
12.5
6.25
3.125
1.5625
0.78125
0.390625
0.195312
0.0976562
3. Same as part 2 except with a
do-while loop
% cat bounce3.cpp
#include<iostream>
using namespace std;
#include<cmath>
int main()
{
double old_height, new_height, difference;
cout << "Enter the initial height of the ball: ";
cin >> old_height;
// use a "post-test" do-while loop
do
{
new_height = old_height / 2.0;
cout << new_height << endl;
difference = fabs(new_height - old_height);
old_height = new_height;
} while (difference > 0.1);
return 0;
}
% g++ bounce3.cpp
cswanson@shemp (~) % a.out
Enter the initial height of the ball: 64
32
16
8
4
2
1
0.5
0.25
0.125
0.0625
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