Tuesday 13 March 2012

The sqrt Function in C & C++

More functions from the  <math.h> or <cmath> header files. Today it’s about the sqrt function.

The sqrt function is straightforward. Given values for x, the function returns y, the square root.


From C11 standard.


Test Code.

I tested the functions in Visual C++ 2010 as an console application.

// The standard library includes the system function.
#include <cstdlib>

// C++ standard I/O library.
#include <cstdio>

// C++ math library.
#include <cmath>

int main()
{
     // Header.
     printf("The sqrt Function in C & C++\n\n");
     printf("Given x, the function returns y equal to the square root of x.\n\n");

     // Counter for loop.
     int i;
     // Argument.
     double n;
     // Result.
     double y;

     printf("  y     x    y    =   x\n\n");
     for (i = 1; i < 10; ++i)
     {
           n = 12.3456 / i;
           y = sqrt(n);
           printf ("%5.4f  x %5.4f = %6.4f\n", y, y, n);
     }
     // Keep console window open.
     system("pause");

     // Return some value.
     return 0;
} // end main


Output.


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