• Hello friends! We often encounter problems related to maths and to deal with it is such a cumbersome task but thankfully not in C programming language as it offers rich set of library functions to deal with mathematical problems.
  • In this post I will explain some of the basic and most frequently used math handling functions. Note that all the math related functions are written inside <math.h> header file so don’t forget to include it in our program to utilize math functions.

floor( ):

  • It returns the nearest integer value which is less than or equal to the floating point argument passed to this function.

Syntax:

double floor ( double x );

Example:

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

void main()
{

   float i=5.1, j=5.9, k=-5.4, l=-6.9;
   printf("floor of  %f is  %f\n", i, floor(i));
   printf("floor of  %f is  %f\n", j, floor(j));
   printf("floor of  %f is  %f\n", k, floor(k));
   printf("floor of  %f is  %f\n", l, floor(l));

}

abs( ):

  • It returns the absolute value of an integer. The absolute value of a number is always positive. Only integer values are supported in C.

Syntax:

int abs ( int n )

Example:

#include <stdio.h>
#include <stdlib.h>

void main()
{
   int m = abs(200);     // m is assigned to 200
   int n = abs(-400);    // n is assigned to -400
   printf("Absolute value of m = %d\n", m);
   printf("Absolute value of n = %d \n",n);
}

Output: 

Absolute value of m = 200   Absolute value of n = 400

round( ):

  • It returns the nearest integer value of the float/double/long double argument passed to this function.
  • If decimal value is from ”.1 to .5″, it returns integer value less than the argument.
  • If decimal value is from “.6 to .9″, it returns the integer value greater than the argument.

Syntax:

Double round(double a);
float roundf (float a);
long double roundl (long double a);

Example:

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

void main()
{
   float i=5.4, j=5.6;
   printf("round of  %f is  %f\n", i, round(i));
   printf("round of  %f is  %f\n", j, round(j));
}

Output:

round of 5.400000 is 5.000000
round of 5.600000 is 6.000000

pow():

  • It is used to find the power of the given number.

Syntax:

double pow (double base, double exponent);

Example:

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

void main()
{
   printf ("2 power 4 = %f\n", pow (2.0, 4.0) );
   printf ("5 power 3 = %f\n", pow (5, 3) );
}

Output:

2 power 4 = 16.000000
5 power 3 = 125.000000

sqrt( ):

  • It is used to find the square root of the given number.

Syntax:

double sqrt (double x);

Example:

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

void main()
{
   printf ("sqrt of 16 = %f\n", sqrt (16) );
   printf ("sqrt of  2 = %f\n", sqrt (2) );
}

Output:

sqrt of 16 = 4.000000
sqrt of 2 = 1.414214

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