sqrt, sqrtf, sqrtl - cppreference.com

##### cppreference.com

##### Search

Create account

##### Namespaces

- Page
- Discussion

##### Variants

##### Views

- View
- Edit
- History

##### Actions

# sqrt, sqrtf, sqrtl

From cppreference.com
< c‎ | numeric‎ | math

Defined in header `<math.h>` |  |
float sqrtf( float arg ); | (1) | (since C99)
double sqrt( double arg ); | (2) |
long double sqrtl( long double arg ); | (3) | (since C99)
Defined in header `<tgmath.h>` |  |
#define sqrt( arg ) | (4) | (since C99)

1-3) Computes square root of `arg`.
4) Type-generic macro: If `arg` has type long double, `sqrtl` is called. Otherwise, if `arg` has integer type or the type double, `sqrt` is called. Otherwise, `sqrtf` is called. If `arg` is complex, then the macro invokes the corresponding complex function (csqrtf, csqrt, csqrtl)

### [edit] Parameters

arg | - | floating point value

### [edit] Return value

If no errors occur, square root of `arg` (√arg), is returned.

If a domain error occurs, an implementation-defined value is returned (NaN where supported)

If a range error occurs due to underflow, the correct result (after rounding) is returned.

### [edit] Error handling

Errors are reported as specified in math_errhandling

Domain error occurs if `arg` is less than zero.

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

- If the argument is less than -0, FE_INVALID is raised and NaN is returned.
- If the argument is +∞ or ±0, it is returned, unmodified.
- If the argument is NaN, NaN is returned

### [edit] Example

Run this code

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

    #pragma STDC FENV_ACCESS ON

    int main(void)
    {
        // normal use
        printf("sqrt(100) = %f\n", sqrt(100));
        printf("sqrt(2) = %f\n", sqrt(2));
        printf("golden ratio = %f\n", (1+sqrt(5))/2);
        // special values
        printf("sqrt(-0) = %f\n", sqrt(-0.0));
        // error handling
        errno = 0; feclearexcept(FE_ALL_EXCEPT);
        printf("sqrt(-1.0) = %f\n", sqrt(-1));
        if(errno = EDOM) perror("    errno == EDOM");
        if(fetestexcept(FE_INVALID)) puts("    FE_INVALID was raised");
    }

Possible output:

    sqrt(100) = 10.000000
    sqrt(2) = 1.414214
    golden ratio = 1.618034
    sqrt(-0) = -0.000000
    sqrt(-1.0) = -nan
        errno = EDOM: Numerical argument out of domain
        FE_INVALID was raised

### [edit] See also

powpowfpowl (C99)(C99) | computes a number raised to the given power (xy) (function) [edit]
cbrtcbrtfcbrtl (C99)(C99)(C99) | computes cubic root (3√x) (function) [edit]
hypothypotfhypotl (C99)(C99)(C99) | computes square root of the sum of the squares of two given numbers (√x2 +y2 ) (function) [edit]
csqrtcsqrtfcsqrtl (C99)(C99)(C99) | computes the complex square root (function) [edit]
C++ documentation for sqrt

Retrieved from "http://en.cppreference.com/mwiki/index.php?title=c/numeric/math/sqrt&oldid=70767"