Pi(π) in C++ with Examples

In this article, we will discuss some of the mathematical function which is used to derive the value of Pi(π) in C++. Method 1: Using acos() function: Approach:

1. The value of Π is calculated using acos() function which returns a numeric value between [-Π, Π].
2. Since using acos(0.0) will return the value for Π/2. Therefore, to get the value of Π:

double pi = 2*acos(0.0);

1. Now the value obtained from above equation is estimated as:

printf("%f\n", pi);

Below is the implementation of the above approach: 

CPP

// C++ program for the above approach

#include "bits/stdc++.h"
using namespace std;

// Function that prints the
// value of pi
void printValueOfPi()
{

    // Find value of pi using
    // acos() function
    double pi = 2 * acos(0.0);

    // Print value of pi
    printf("%f\n", pi);
}

// Driver Code
int main()
{
    // Function that prints
    // the value of pi
    printValueOfPi();
    return 0;
}

Output:

3.141593

Time Complexity: O(1)

Auxiliary Space: O(1)

Method 2: Using asin() function: Approach:

1. The value of Π is calculated using asin() function which returns a numeric value between [-Π, Π].
2. Since using asin(1.0) will return the value for Π/2. Therefore, to get the value of Π:

double pi = 2*asin(1.0);

1. Now the value obtained from above equation is estimated as:

printf("%f\n", pi);

Below is the implementation of the above approach: 

CPP

// C++ program for the above approach

#include "bits/stdc++.h"
using namespace std;

// Function that prints the
// value of pi
void printValueOfPi()
{

    // Find value of pi using
    // asin() function
    double pi = 2 * asin(1.0);

    // Print value of pi
    printf("%f\n", pi);
}

// Driver Code
int main()
{
    // Function that prints
    // the value of pi
    printValueOfPi();
    return 0;
}

Output:

3.141593

Time Complexity: O(1)

Auxiliary Space: O(1)

Method 3: Using inbuilt constant value define in the “cmath” library: The value of Pi(π) can directly written using the constant stored in cmath library. The name of the constant is M_PI. Below is the program for printing the value of Pi: 

CPP

// C++ program for the above approach
#include "cmath"
#include "iostream"
using namespace std;

// Function that prints the
// value of pi
void printValueOfPi()
{
    // Print value of pi
    printf("%f\n", M_PI);
}

// Driver Code
int main()
{
    // Function that prints
    // the value of pi
    printValueOfPi();
    return 0;
}

Output:

3.141593

Time Complexity: O(1)

Auxiliary Space: O(1)