# C++ exp()

The exp() function in C++ returns the exponential (Euler's number) e raised to the given argument.

This function is defined in <cmath> header file.

[Mathematics] ex = exp(x) [C++ Programming]

## exp() prototype [As of C++ 11 standard]

double exp(double x);
float exp(float x);
long double exp(long double x);
double exp(T x); // For integral type

The exp() function takes a single argument and returns exponential value in type double, float or long double type.

## exp() Parameters

The exp() function takes a single mandatory argument and can be any value i.e. negative, positive or zero.

## exp() Return value

The exp() function returns the value in the range of [0, ∞].

If the magnitude of the result is too large to be represented by a value of the return type, the function returns HUGE_VAL with the proper sign, and an overflow range error occurs.

## Example 1: How exp() function works in C++?

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
double x = 2.19, result;

result = exp(x);
cout << "exp(x) = " << result << endl;

return 0;
}

When you run the program, the output will be:

exp(x) = 8.93521

## Example 2: exp() function with integral type

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
long int x = 13;
double result;

result = exp(x);
cout << "exp(x) = " << result << endl;

return 0;
}

When you run the program, the output will be:

exp(x) = 442413