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C Math Functions

Math Functions

There is also a list of math functions available, that allows you to perform mathematical tasks on numbers.

To use them, you must include the math.h header file in your program:

#include <math.h>

Square Root

To find the square root of a number, use the sqrt() function:


printf("%f", sqrt(16));
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Round a Number

The ceil() function rounds a number of upwards to its nearest integer, and the floor() function rounds a number of downwards to its nearest integer, and returns the result:


printf("%f", ceil(1.4));
printf("%f", floor(1.4));
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The pow() function returns the value of x to the power of y (xy):


printf("%f", pow(4, 3));
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Other Math Functions

A list of other popular math functions (from the <math.h> library) can be found in the table below:

Function Description
abs(x) Returns the absolute value of x
acos(x) Returns the arccosine of x
asin(x) Returns the arcsine of x
atan(x) Returns the arctangent of x
atan2(y, x) Returns the arctangent of y/x
ceil(x) Returns the smallest integer greater than or equal to x
cbrt(x) Returns the cube root of x
cos(x) Returns the cosine of x
cosh(x) Returns the hyperbolic cosine of x
exp(x) Returns the value of Ex (the exponential of the number x)
fabs(x) Returns the absolute value of x
floor(x) Returns the largest integer that is less than or equal to x
fmod(x, y) Returns the remainder of dividing x by y
frexp(x, exp) Decomposes the number x into whole and fractional parts
hypot(x, y) Returns the hypotenuse of a right triangle with legs x and y
ldexp(x, exp) Multiplies the number x by 2 to the power of exp
log(x) Returns the natural logarithm of x
log10(x) Returns the decimal logarithm of x
modf(x, ip) Factors a number x into its integer and fractional parts and returns the fractional part
pow(x, y) Returns x to the power of y
sin(x) Returns the sine of x (x in radians)
sinh(x) Returns the hyperbolic sine of x
sqrt(x) Returns the square root of x
tan(x) Returns the tangent of x
tanh(x) Returns the hyperbolic tangent of x
trunc(x) Returns the integer part of x

All of these functions accept arguments of type double unless otherwise specified.