Programming

// sintab.cpp
// Creates a tangent function table
#include <iostream>
#include <iomanip>
#include <cmath>

using namespace std;

#define PI      3.1415926536
#define START   0.0                      // Lower limit
#define END     (2.0 * PI)               // Upper limit
#define STEP    (PI / 8.0)               // Step width
#define HEADER  (cout << " ***** Tangent Function Table *****\n\n")
int main()
{
  HEADER;                                // Title
                                         // Table Head:
  double x;
  cout << setw(16) << "x" << setw(20) << "tan(x)\n"
       << "-----------------------------------------"
       << fixed << endl;
  
  for( x = START; x < END + STEP/2; x += STEP)
    {
      if ( x = 0.5 * PI || x = 1.5 * PI )
        cout << "tangent is undefined." << endl;
      else
        cout << setw(20) << x << setw(16) << tan(x) << endl << endl << endl;
    }
  return 0;
}

if ( x == 0.5 * PI || x == 1.5 * PI )

(( x == (0.5 * PI)) || (x == (1.5 * PI) ))