# <QtMath> - Generic Math Functions

The <QtMath> header file provides various math functions. More...

## Functions

 qreal qAcos(qreal v) qreal qAsin(qreal v) qreal qAtan2(qreal y, qreal x) qreal qAtan(qreal v) int qCeil(qreal v) qreal qCos(qreal v) float qDegreesToRadians(float degrees) double qDegreesToRadians(double degrees) qreal qExp(qreal v) qreal qFabs(qreal v) int qFloor(qreal v) qreal qLn(qreal v) quint32 qNextPowerOfTwo(quint32 value) quint64 qNextPowerOfTwo(quint64 value) quint32 qNextPowerOfTwo(qint32 value) quint64 qNextPowerOfTwo(qint64 value) qreal qPow(qreal x, qreal y) float qRadiansToDegrees(float radians) double qRadiansToDegrees(double radians) qreal qSin(qreal v) qreal qSqrt(qreal v) qreal qTan(qreal v)

## Detailed Description

These functions are partly convenience definitions for basic math operations not available in the C or Standard Template Libraries.

The header also ensures some constants specified in POSIX, but not present in C++ standards (so absent from <math.h> on some platforms), are defined:

ConstantDescription
`M_E`The base of the natural logarithms, e = exp(1)
`M_LOG2E`The base-two logarithm of e
`M_LOG10E`The base-ten logarithm of e
`M_LN2`The natural logarithm of two
`M_LN10`The natural logarithm of ten
`M_PI`The ratio of a circle's circumference to diameter, π
`M_PI_2`Half M_PI, π / 2
`M_PI_4`Quarter M_PI, π / 4
`M_1_PI`The inverse of M_PI, 1 / π
`M_2_PI`Twice the inverse of M_PI, 2 / π
`M_2_SQRTPI`Two divided by the square root of pi, 2 / √π
`M_SQRT2`The square root of two, √2
`M_SQRT1_2`The square roof of half, 1 / √2

## Function Documentation

### qrealqAcos(qrealv)

Returns the arccosine of v as an angle in radians. Arccosine is the inverse operation of cosine.

### qrealqAsin(qrealv)

Returns the arcsine of v as an angle in radians. Arcsine is the inverse operation of sine.

### qrealqAtan2(qrealy, qrealx)

Returns the arctangent of a point specified by the coordinates y and x. This function will return the angle (argument) of that point.

### qrealqAtan(qrealv)

Returns the arctangent of v as an angle in radians. Arctangent is the inverse operation of tangent.

### intqCeil(qrealv)

Return the ceiling of the value v.

The ceiling is the smallest integer that is not less than v. For example, if v is 41.2, then the ceiling is 42.

### qrealqCos(qrealv)

Returns the cosine of an angle v in radians.

This function converts the degrees in float to radians.

Example:

```float degrees = 180.0f

This function was introduced in Qt 5.1.

This function converts the degrees in double to radians.

Example:

```double degrees = 180.0

This function was introduced in Qt 5.1.

### qrealqExp(qrealv)

Returns the exponential function of `e` to the power of v.

### qrealqFabs(qrealv)

Returns the absolute value of v as a qreal.

### intqFloor(qrealv)

Return the floor of the value v.

The floor is the largest integer that is not greater than v. For example, if v is 41.2, then the floor is 41.

### qrealqLn(qrealv)

Returns the natural logarithm of v. Natural logarithm uses base e.

### quint32qNextPowerOfTwo(quint32value)

This function returns the nearest power of two greater than value. For 0 it returns 1, and for values larger than or equal to 2^31 it returns 0.

This function was introduced in Qt 5.4.

### quint64qNextPowerOfTwo(quint64value)

This function returns the nearest power of two greater than value. For 0 it returns 1, and for values larger than or equal to 2^63 it returns 0.

This function was introduced in Qt 5.4.

### quint32qNextPowerOfTwo(qint32value)

This function returns the nearest power of two greater than value. For negative values it returns 0.

This function was introduced in Qt 5.4.

### quint64qNextPowerOfTwo(qint64value)

This function returns the nearest power of two greater than value. For negative values it returns 0.

This function was introduced in Qt 5.4.

### qrealqPow(qrealx, qrealy)

Returns the value of x raised to the power of y. That is, x is the base and y is the exponent.

This function converts the radians in float to degrees.

Example:

```float radians = float(M_PI)

This function was introduced in Qt 5.1.

This function converts the radians in double to degrees.

Example:

```double radians = M_PI

This function was introduced in Qt 5.1.

### qrealqSin(qrealv)

Returns the sine of the angle v in radians.

### qrealqSqrt(qrealv)

Returns the square root of v. This function returns a NaN if v is a negative number.