Pi(π) in C++ with Example

Question

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);
   

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

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

Below is the implementation of the above approach:

// C++ program for the above approach 

#include "bits/stdc++.h" 

using namespace std; 

/// 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; 

} 

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);
   

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

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

Below is the implementation of the above approach:

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// 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

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:

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// 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