Mathematical functions in C Programming Language

Mathematical functions in C Language

The C language provides the following mathematical functions. To use these functions, you must add them to the program file header:

# Include <math. h>

During compilation, the "-lm" parameter must be added to the mathematical function library, for example, "gcc-LM test. c 」.

For the independent variables of the function and the return value types, see the Declaration of the type before the independent variables or functions.

The function is already in "math. H "or other header files have been declared, so you do not need to add a type declaration during use, for example," Y = sin (x );」, you do not need to write "Y = double sin (Double X );」.

Function Description

Double sin (Double X)

Sine function value of X

Double cos (Double X)

Returns the cosine of X.

Double Tan (Double X)

Returns the tangent of X.

Double asin (Double X)

The inverse sine function value of X sin-1x, the value of X between [-], the return value between [-P/2, P/2]

Double ACOs (Double X)

Returns the inverse cosine function value of cos-1x between [-] and between [-P/2, P/2 ].

Double atan (Double X)

Returns the arc tangent function value tan-1x between [-P/2, P/2 ].

Double atan2 (Double Y, double X)

The arc tangent function value of Y/X Tan-1 (y/X). The return value is between [-p, p ].

Double sinh (Double X)

Returns the hyperbolic sine of X.

Double cosh (Double X)

Returns the hyperbolic cosine of X.

Double Tanh (Double X)

Returns the hyperbolic tangent of X.

Double exp (Double X)

X's exponential function ex

Double Log (Double X)

Natural logarithm Ln (x) of x, x> 0

Double log10 (Double X)

The base number of X is the logarithm of 10, log10x, x> 0

Double POW (Double X, Double Y)

X to the power of Y XY

Double SQRT (Double X)

The root number of X √ x

Double Ceil (Double X)

Minimum integer not less than X (but its type is double)

Double floor (Double X)

The maximum integer not greater than X (but its type is double)

Int ABS (int x)

Absolute Value of integer x |

Long labs (long X)

Absolute Value of long integer x |

Double FABS (Double X)

Absolute value of real number x |

Double ldexp (Double X, int N)

X? 2N

Double fmod (Double X, Double Y)

The remainder of the Floating Point Number of x/y. the symbol is the same as that of X.

Function Name: atof
Function: converts a string to a floating point number.
Usage: Double atof (const char * nptr );
Program example:
# Include <stdlib. h>
# Include <stdio. h>

Int main (void)
{
Float F;
Char * STR = "12345.67 ";

F = atof (STR );
Printf ("string = % s float = % F/N", STR, F );
Return 0;
}

Function Name: atoi
Function: converts a string to an integer.
Usage: int atoi (const char * nptr );
Program example:
# Include <stdlib. h>
# Include <stdio. h>

Int main (void)
{
Int N;
Char * STR = "12345.67 ";

N = atoi (STR );
Printf ("string = % s integer = % d/N", STR, N );
Return 0;
}

Function Name: atol
Function: converts a string to an integer.
Usage: Long atol (const char * nptr );
Program example:

# Include <stdlib. h>
# Include <stdio. h>

Int main (void)
{
Long L;
Char * STR = "98765432 ";

L = atol (lstr );
Printf ("string = % s integer = % LD/N", STR, L );
Return (0 );
}