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      sqrt, sqrtf, sqrtl

      From cppreference.com
      < c‎ | numeric‎ | math
       
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      Defined in header <math.h>
      float       sqrtf(float arg );
      		 (1) (since C99)
      double      sqrt(double arg );
      		 (2)
      longdouble sqrtl(longdouble 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 longdouble, sqrtl is called. Otherwise, if arg has integer type or the type double, sqrt is called. Otherwise, sqrtf is called. If arg is complex or imaginary, then the macro invokes the corresponding complex function (csqrtf, csqrt, csqrtl).

      Contents

      [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]Notes

      sqrt is required by the IEEE standard to be correctly rounded from the infinitely precise result. In particular, the exact result is produced if it can be represented in the floating-point type. The only other operations which require this are the arithmetic operators and the function fma. Other functions, including pow, are not so constrained.

      [edit]Example

      Run this code
      #include <errno.h>#include <fenv.h>#include <math.h>#include <stdio.h>// #pragma STDC FENV_ACCESS ON   int main(void){// normal useprintf("sqrt(100) = %f\n", sqrt(100));printf("sqrt(2) = %f\n", sqrt(2));printf("golden ratio = %f\n", (1+ sqrt(5))/2);   // special valuesprintf("sqrt(-0) = %f\n", sqrt(-0.0));   // error handlingerrno=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]References

      • C23 standard (ISO/IEC 9899:2024):
      • 7.12.7.5 The sqrt functions (p: TBD)
      • 7.25 Type-generic math <tgmath.h> (p: TBD)
      • F.10.4.5 The sqrt functions (p: TBD)
      • C17 standard (ISO/IEC 9899:2018):
      • 7.12.7.5 The sqrt functions (p: TBD)
      • 7.25 Type-generic math <tgmath.h> (p: TBD)
      • F.10.4.5 The sqrt functions (p: TBD)
      • C11 standard (ISO/IEC 9899:2011):
      • 7.12.7.5 The sqrt functions (p: 249)
      • 7.25 Type-generic math <tgmath.h> (p: 373-375)
      • F.10.4.5 The sqrt functions (p: 525)
      • C99 standard (ISO/IEC 9899:1999):
      • 7.12.7.5 The sqrt functions (p: 229-230)
      • 7.22 Type-generic math <tgmath.h> (p: 335-337)
      • F.9.4.5 The sqrt functions (p: 462)
      • C89/C90 standard (ISO/IEC 9899:1990):
      • 4.5.5.2 The sqrt function

      [edit]See also

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