C Language: Maths Inbuilt Functions

Mathematical functions

In C Language we have a number of inbuilt Mathematical functions which help us to perform various operations.

Header file: math.h 

abs():

Helps us to find the absolute value of an integer value

labs():

Helps us to find the absolute value of a value of type long.

fabs() or fabsl():

Helps us to find the absolute value of a value of type float.

#include <stdio.h>
#include<math.h>

int main()
{
    int n1 = -1234;
    float n2 = -1234.0;
    long n3,x = -12345678L;
    int n;
    printf("(int value) number: %d  absolute value: %d\n",n1,abs(n1));
    printf("Enter any no ");
    scanf("%d",&n);
    printf("(int) abs value of %d is %d\n",n,abs(n));
    //long
    n3= labs(x);
    printf("(long value)number: %ld abs value: %ld\n", x, n3);
    //float value
    printf("(float value)number:%f abs value: %f\n",n2,fabs(n2));
	return 0;
}

/* Output */

(int value) number: -1234 absolute value: 1234
Enter any no -65
(int) abs value of -65 is 65
(long value)number: -12345678 abs value: 12345678
(float value)number:-1234.000000 abs value: 1234.000000

ceil(x):

Helps us to find upper side nearest integer. i.e. finds the smallest integer not < x.

floor(x):

Helps us to find lower side nearest integer i.e. finds the largest integer not > x.

#include <stdio.h>
#include<math.h>

int main()
{
    double n = 123.54;
    printf("number: %5.2lf  ceil: %5.2lf Floor: %5.2lf\n", n,ceil(n),floor(n));
    n=-123.54;
    printf("number: %5.2lf  ceil: %5.2lf Floor: %5.2lf\n", n,ceil(n),floor(n));
	return 0;
}

/* Output */

number: 123.54 ceil: 124.00 Floor: 123.00
number: -123.54 ceil: -123.00 Floor: -124.00

modf():

breaks the double x into two parts: the integer and the fraction. It

modfl():

modfl is the long double version of modf.

#include <stdio.h>
#include<math.h>

int main()
{
    double fraction, integer;
    double number = 100.56;
    fraction = modf(number, &integer);
    printf("The whole and fractional parts of \n%lf are %lf  and %lf\n",number, integer, fraction);
	return 0;
}

/* Output */

The whole and fractional parts of
100.560000 are 100.000000 and 0.560000