Pi(π) in C++ with Examples

Last Updated : 16 Jun, 2022

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:

The value of Π is calculated using acos() function which returns a numeric value between [-Π, Π].
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);

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:

The value of Π is calculated using asin() function which returns a numeric value between [-Π, Π].
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);

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; 
} 