C++ Math tgamma

The tgamma function calculates the gamma function value of the input argument provided to the function.

Suppose a number is x:

Syntax

float tgamma(float x);
double tgamma(double x);
long double tgamma(long double x);
double tgamma(double x);

Parameter

x : It is a floating point value.

Return value

It returns the gamma function value of x.

Example 1

Let's examine a straightforward example where x equals zero.

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
     float x= 0.0;
     cout<<"Value of x is : "<<x<<'\n';
     cout<<"tgamma(x) : "<<tgamma(x);
     return 0;}

Output:

Value of x is : 0
tgamma(x) : inf

When x equals zero in the example provided, the function tgamma will result in positive infinity.

Example 2

Let's examine a basic scenario where the value of x is below zero.

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
     int x= -6;
     cout<<"Value of x is : "<<x<<'\n';
     cout<<"tgamma(x) : "<<tgamma(x);
     return 0;
}

Output:

Value of x is : -6
tgamma(x) : nan

When x is a negative integer in the given scenario, the tgamma function will yield a result of NaN.

Example 3

Let's consider a basic scenario where the value of x approaches negative infinity.

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
     float x= -9.0/0.0;
     cout<<"Value of x is : "<<x<<'\n';
     cout<<"tgamma(x): "<<tgamma(x);
     return 0;
}

Output:

Value of x is : -inf
tgamma(x): nan

When x tends to negative infinity in the given scenario, the value of x is negative infinity. Consequently, the function tgamma will output a nan (not a number).

Example 4

Let's consider a basic scenario where the value is positive infinity.

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
     float x= 7.8/0.0;
     cout<<"Value of x is : "<<x<<'\n';
     cout<<"tgamma(x) : "<<tgamma(x);
     return 0;
}

Output:

Value of x is : inf
tgamma(x) : inf

In the provided illustration, the value of x is positive infinity. Consequently, the tgamma function yields positive infinity.

Example 5

Let's consider a basic scenario where the value of x is NaN.

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
     float x= 0.0/0.0;
     cout<<"Value of x is : "<<x<<'\n';
     cout<<"tgamma(x) : "<<tgamma(x);
    return 0;
}

Output:

Value of x is : -nan
tgamma(x) : -nan

In the previous example, the variable x is set to NaN. Consequently, the tgamma function will yield NaN as a result.