Math Functions in C Programming Languages

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Introduction to Math Functions in C Programming Languages

This article lists the different mathematical functions used in C programming languages with working code illustration. Computers do huge mathematical calculations and analyses of huge numbers, to do so we have used math features in C. Before Starting with, we need to know the C languages use header/library called Math.h for various mathematical functions. This helps in calculating trigonometric operations, logarithms, absolute values, square roots. So, let us explore the different types of functions used in this library. All these functions take double as a data type and return the same. Math functions and constants are defined in the C library, in <math.h> header file, which can be used to perform mathematical calculations. C Programming allows us to perform mathematical operations through the functions defined in <math.h> header file. The <math.h> header file contains various methods for performing mathematical operations such as sqrt(), pow(), ceil(), floor() etc.

The math.h header defines various C mathematical functions. All the functions available in this library take double as an argument and return double as the result. Let us discuss some important C math functions one by one.

Math Functions in C Programming Languages

There are various methods in math.h header file. The commonly used functions of math.h header file are given below.

Various Math Functions in C

Let’s see various functions defined in math.h and the Math library is categorized into three main types: Trigonometric functions, math functions, Log/expo functions. To implement the below functions, it is mandatory to include<cmath.h> or <math.h> in the code.

1.  floor (double a)

This function returns the largest integer value not greater than ‘a’ value. It rounds a value and returns a double as a result. It behaves differently for negative numbers, as they round to the next negative number.

Ex: floor (7.2) is 7.0

   floor (-7.2) is -8.0

Example:

This program illustrates how to compute the floor for the declared value and rounds to the next value 10.

Programs of Floor Functions

Output of Floor Functions

2.   ceil ()

Syntax: 

double ceil (double b)

This function returns the smallest integer value that is greater or equal to b and rounds the value upwards. For a negative value, it moves towards the left. Example 3.4 returns -3 has the output. 

Example:

This program explains by taking input in the float argument and returns the ceil value.

Programs of Ceil Functions

Output of Ceil Functions

3.   Sqrt ()

The C library function double sqrt(double x) returns the square root of x. 

Syntax

double sqrt(double x);

Example:

Programs of sqrt() Functions

Output of sqrt() Functions

Square root of 225.000000 is 15.000000

Square root of 300.000000 is 17.320508

4.   round ()

This function rounds the nearest value of a given input. It throws out the error if the value is too large. Other functions like lround (), llround () also rounds the nearest integer.

Syntax:

int round(arg)

Example:

Programs of round() Functions

Output of round() Functions

The below code is very simple which does round off to the nearest ‘r’ value in the for loop.

5.   pow ()

The C library function double pow(double x, double y) returns x raised to the power of y
i.e. xy.

Syntax
double pow(double x, double y);

Example

Programs of pow() Functions

Output of pow() Functions

Value 8.0 ^ 3 = 512.000000

Value 3.05 ^ 1.98 = 9.097324

6.   fabs()

The C library function double fabs(double x) returns the absolute value of x.

Syntax

syntax: double fabs(double x)

Example

Programs of fabs() Functions

Output of fabs() Functions

The absolute value of 1234 is 1234.000000

The absolute value of -344 is 344.000000

7.   trun()

This function helps in truncating the given value. It returns integer values. To truncate floating and double values truncf (), truncl () are used.

Syntax:

double trunc(a);

Example:

Below source code takes two input values a, b to truncate the double values.

Programs of trun() Functions

#include <stdio.h>

#include <math.h>

void main() {

double m, n, a, b;

a = 56.16;

b = 85.74;

m = trunc(a);

n = trunc(b);

printf("The value of a: %lf\n",m);

printf("The value of a: %lf\n",n);

}

Output of trun() Functions

8.   fmod()

This function returns the remainder for the given two input values when m divided by n.

Syntax:

double fmod(double I, double j)

Example:

In the below example it takes two values from the user to compute the remainder using fmod() function.

Program of fmod() Functions

#include<stdio.h>

#include<math.h>

int main()

{

double fiN;

double secN;

double n;

printf("Enter the first number: ");

scanf("%lf",&fiN);

printf("Enter the second number: ");

scanf("%lf",&secN);

printf("fmod(firstNumber,secondNumber) is %lf \n",fmod(fiN,secN));

}

Output of fmod() Functions

Trigonometric Functions

Below are the different functions of Trigonometric:

1)  sin()

This built-in function gives sine value of the given number, calculates floating-point values. asin() computes arc, for hyperbolic it is sinh().

Syntax:

return type sin(y);

y returns value in radians and return type takes double.

Example:

In the following source code, I have taken two different input values to calculate sin value and returns double.

Program of sin() Functions

Output of sin() Functions

2)  cos()

This math function determines the trigonometric cosine value for the given element.

Syntax: 

return type cos(argument);

Example

Programs of cos() Functions

Output of cos() Functions 

3)  tan()

This math library function calculates tangent values of the angle for the mathematical expression and measured in radians.

It can be declared as

double tan(arguments);

Example

In the following source code, tan value is calculated for the following angles which is incremented using for loop.

Program of tan() Functions

# include <stdio.h>

# include <conio.h>

# include <math.h>

void main()

{

float z;

int k;

char ch;

printf("\nAngle \t Tan \n");

for(k = 0; k <= 180; k = k + 30)

{

z = k * 3.14159 / 180;

printf("\n %d, %5.2f”, k, tan(z));

}

getch();

}

Output of tan() Functions

Log Arithmetic Functions

Below are the different functions of log arithmetic:

    a).        exp()

This function does computation on exponential for a given value(ex). There are also other subtypes like frexp(), Idexp() returning mantissa and multiplied to the power of x.

Syntax: 

return type exp(value);

Example:

The program takes numeric value from the user to compute the exponent for a given value and returns double.

Program of exp() Functions 

Output of exp() Functions

    b) .        log()

This function returns the logarithm value of a given number. (to the base e. loge)

Syntax: 

double log(arg);

Example:

In the following example, log value for the given number is calculated using function. User-defined function lgm() does computation and function is called in the main function.

Program of log() Functions 

Output of log() Functions

Example of Math Functions in C Program

Let's see a simple example of math functions found in math.h header file.

Programs of Example of Math Functions in C Program

Output of Example of Math Functions in C Program