C++ ldexp() function usage and example

C++ Library Function <cmath>

C ++The ldexp(x, exp) function in the product uses two parameters: x and exp, and returns x and2product, whose product is the power of exp, that is, x * 2 ^exp.

The function is in<cmath>defined in the header file.

Mathematically

ldexp(x, exp) = x　*　2exp

ldexp() prototype [from C ++ 11Standard starts]

double ldexp(double x, int exp);
float ldexp(float x, int exp);
long double ldexp(long double x, int exp);
double ldexp(T x, int exp);　//for integer

The ldexp() function has two parameters and returns a value of type double, float, or long double.

ldexp() parameter

• x -representing a floating-point value with significant digits.

• exp -exponent value.

ldexp() return value

ldexp() function returns the expression x * 2 ^expvalue.

Example1：ldexp() function in C ++How does it work in C?

#include <iostream>
#include <cmath>
using namespace std;
int main ()
{
	double x =　13.056, result;
	int exp =　2;
	result = ldexp(x, exp);
	cout << "ldexp(x, exp) = " << result << endl;
	return 0;
}

When running the program, the output is:

ldexp(x, exp) =　52.224

Example2：An integer type ldexp() function

#include <iostream>
#include <cmath>
using namespace std;
int main ()
{
	double result;
	int x =　25, exp =　5;
	result = ldexp(x, exp);
	cout << "ldexp(x, exp) = " << result << endl;
	return 0;
}

When running the program, the output is:

ldexp(x, exp) =　800

　 C++ Library Function <cmath>