C++ isnormal()

In C++, the isnormal() function determines whether a floating-point number is normal, meaning it is non-zero, not subnormal, not infinite, and not NaN. It is useful when performing numerical computations that require standard floating-point numbers.

Syntax

bool isnormal(double x);

Or, alternatively:

bool isnormal(float x);

Or, alternatively:

bool isnormal(long double x);

Parameters:

• x : The floating-point number (float, double, or long double) to be checked.

Return value:

• true if x is a normal floating-point number.
• false if x is zero, subnormal, infinite, or NaN.

Example 1: Checking normal and zero numbers

In this example, a normal number and zero are checked using isnormal(). The normal number returns true, while zero returns false:

#include <iostream>
#include <cmath>

int main() {
  double a = 5.0;
  double b = 0.0;

  std::cout << std::boolalpha;
  std::cout << "isnormal(a): " << std::isnormal(a) << "\n";
  std::cout << "isnormal(b): " << std::isnormal(b) << "\n";

  return 0;
}

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The output of this code is:

isnormal(a): true
isnormal(b): false

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Codebyte Example: Checking subnormal, infinite, and NaN numbers

In this example, subnormal, infinite, and NaN numbers are checked. All of these are not considered normal, so isnormal() returns false for each:

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Frequently Asked Questions

1. How to use not equal in C++?

The not equal operator in C++ is written as !=. It compares two values and returns true if they are not equal, otherwise false. Example:

#include <iostream>
int main() {
  int a = 5, b = 10;
  if (a != b) {
    std::cout << "a and b are not equal\n"; // outputs: a and b are not equal

  }
  return 0;
}

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2. What is isdigit() in C++?

The isdigit() function checks if a character is a decimal digit ('0'–'9'). It is declared in <cctype> or <ctype.h> and returns a non-zero value (true) if the character is a digit, otherwise 0 (false).

3. What are the four types of functions in C++?

The four types of functions in C++ based on parameters and return type are:

1. Function with no arguments and no return value
2. Function with arguments and no return value
3. Function with no arguments but returns a value
4. Function with arguments and returns a value