Example 1

/*  the program shows how to use math liabrary  */

# include <iostream.h>
# include <math.h>

int abs ( void );
int log ( void );
int atof ();
int ceil ();
int exp ();
int pow ();
int sqrt ();

main()
{
   log ();
   abs ();
   atof ();
   ceil ();
   exp ();
   pow ();
   sqrt ();
   return 0;
}

int log ( void )    // how to use log
//logarithms function
{
   double result;
   double x = 8.6872;
   result = log ( x );
   cout << result << endl << endl;
   return 0;
}

int abs ()         // how to use abs
//absolute value (positive from negative)
{
   int a = - 2;
   a = abs ( a );
   cout << a << endl << endl;
   return 0;
}

int atof ()       // how to use atof
//turn a string into a float
{
   double c;
   char b [] = { '1', '2', '3', '4' };
   c = atof (b);
   cout << c << endl << endl;
   return 0;
}

int ceil ()      // how to use ceil
// highest number function
{
   double d=2.9;
   int e;
   e = ceil ( d );
   cout << e << endl << endl;
   return 0;
}

int exp ()      // how to use exp
//exponents function
{
   int f;
   f = exp ( 3 );
   cout << f << endl << endl;
   return 0;
}

int pow ()     // how to use pow
//powers function
{
   int p = 5;
   int q;
   q = pow ( p , 3 );
   cout << q << endl << endl;
   return 0;
}

int sqrt ()   // how to use sqrt
//square root function
{
   int y = 9;
   int z;
   z = sqrt ( y );
   cout << z << endl << endl;
   return 0;
}