Long Double in C

1. the long double in C
2. Format Specifier of Datatype in C
3. Create a Project in C
4. Implement Long Double in C

This tutorial will explain the datatype of long double in C language and its format specifier.

the long double in C

In C language, long double is used as a variable’s datatype. We must specify the data type and the variable name in the variable declaration statement.

For example, In the following statement, long double is the data type, and d is the variable’s name.

long double d;

In C language, we have three data types used for decimal numbers. They are pretty similar, but their precision value is different, and their bytes in memory are different.

These data types are float, double, and long double.

• float requires 4 bytes in memory, and its precision is up to 6 digits.
• double requires 8 bytes in memory, and its precision is up to 15 digits.
• long double requires 10 bytes in memory, and its precision is up to 19 digits.

Format Specifier of Datatype in C

Format specifiers specify the format in which the value of a variable is represented on the screen. These are defined in the format string.

In the following code example, we used the format specifier of float, double and long double.

Code:

#include <stdio.h>
int main() {
  float a = 5.5;
  double b = 6.78;
  long double c = 4.5678;
  printf("The value of a is %f\n", a);
  printf("The value of b is %lf\n", b);
  printf("The value of a is %Lf\n", c);
  return 0;
}

The %f, %lf, and %Lf format specifiers of float, double, and long double, respectively.

Output:

The value of a is 5.500000
The value of b is 6.780000
The value of a is 4.567800

Create a Project in C

Implement Long Double in C

This code snippet shows the behavior of float, double and long double with decimal numbers in exponential form.

Code:

#include <stdio.h>

int main(void) {
  float a = 450000.0;
  double b = 3.314e3;
  long double c = 8.567e-2;

  printf("%f will be displayed as %e\n", a, a);
  printf("%lf will be displayed as %e\n", b, b);
  printf("%Lf will be displayed as %Le\n", c, c);
  return 0;
}

First, we have a standard input/ output header file. Then, in the main function, we initialized the three variables having decimal numbers in exponential form.

The three variables have different datatypes. Then in the format string, we have displayed all three numbers using their respective format specifiers.

After that, the function returns 0 because the main function has a return type of integer.

Output:

450000.000000 will be displayed as 4.500000e+05
3314.000000 will be displayed as 3.314000e+03
0.085670 will be displayed as 8.567000e-02