Authors:
Walter Savitch ,julia Lobur
Chapter:
More Flow Of Control
Exercise:
Programming Projects
Question:12 | ISBN:9780321531346 | Edition: 7
Question
An approximate value of pi can be calculated using the series given below:
pi = 4 [ 1 − 1/3 + 1/5 − 1/7 + 1/9 ... + ((−1)n)/(2n+1) ]
Write a C++ program to calculate the approximate value of pi using this series. The program takes an input n that determines the number of terms in the approximation of the value of pi and outputs the approximation.Include a loop that allows the user to repeat this calculation for new values n until the user says she or he wants to end the program.
Answer
#include<iostream>
#include<cmath>
using namespace std;
int main()
{
//variables
double n;
double pi=0;
char repeatInput;
int i,j,k=1;
do
{
//User input
cout<<"Enter n value:";
cin>>n;
//Compute pi value
for(i=1,j=2;i<n;i++,j++)
{
pi=pi+pow((-1),j)*4/k;
k=k+2;
}
//Print output of pi value
cout<<"pi value:"<<pi<<endl;
cout<<"Type 'y' to continue (or) Exit:";
cin>>repeatInput;
}while(repeatInput =='y' || repeatInput =='Y');
}
Output of code:
Enter n value:3.14
The approximation of the value of pi: 3.46667
Type 'y' to continue (or) Exit:y
Enter n value:15
The approximation of the value of pi: 3.73297
Type 'y' to continue (or) Exit:y
Enter n value:100
The approximation of the value of pi: 3.80036
Type 'y' to continue (or) Exit: Exit