Thread: How to convert angle degrees into radians

Mat...I tried this,but it returns wrong values -:

Code:

void Program::Trigonometry()
{
                    double pi = 3.1416; //Again for trigo.
                    if (g[0] == 'M' || 'm')
                     {
                           setcolor(7);
                           cout << "Enter angle theta (degrees) -";
                           cin >> degrees;
                           a == degrees * (pi/180);
                           Sine = sin (a * (180/pi));
                           Cosine = cos (a * (180/pi)) ;
                           Tangent = tan (a * (180/pi));
                           Arctan = atan (a * (180/pi));
                           Arccos = acos (a * (180/pi));
                           Arcsine = asin (a * (180/pi));
                           
                     }
                     else if (g[0] == 'N' || 'n')
                     { 
                           setcolor(7);
                           cout << "Enter angle theta(radians) -";
                           cin >> radians;
                           cin.ignore(); 
                           a == radians;
                           Sine = sin (a);
                           Cosine = cos (a);
                           Tangent = tan (a);
                           Arctan = atan (a);
                           Arccos = acos (a);
                           Arcsine = asin (a);
                     }
                           cout << "\nThe trigonometric ratios are as follows -:\n";
                           setcolor(14);
                           cout << "Sin theta = " << Sine << endl;
                           cout << "Cos theta = " << Cosine << endl;
                           cout << "Tan theta = " << Tangent << endl;
                           cout << "Inverse Sin(Arcsine) theta = " << Arcsine << endl;
                           cout << "Inverse Cos(Arccos) theta = " << Arccos << endl;
                           cout << "Inverse Tan(Arctan) theta = " << Arctan << endl;
}

I try any angle,'cos' always comes 1,and the rest the same garbage.

Code:

a == degrees * (pi/180);

Guess you want

Code:

a = degrees * (pi/180);

Kurt
EDIT:
same here

Code:

a == radians;

The trig functions take arguments in radians. You've correctly converted a from degrees to radians, then incorrectly converted it right back to degrees inside the arguments to each of the trig functions.

I was thinking pretty much the same thing...it accepts arguements in radians. How do I make it accept args in degrees? Then I'd convert degrees to radians,feed it to the computer and get an output based on that. And Salem that if else works anyway :P

Hmm k I see,I'll implement what you said...but what about the accepting args in degrees part..some help on that please

Originally Posted by SVXX

Hmm k I see,I'll implement what you said...but what about the accepting args in degrees part..some help on that please

You don't give args in degrees, you give them in radians (why did you convert the angle from degrees to radians if you didn't think you were supposed to use it?). For example:

Code:

std::cin >> degrees;
a = degrees * (pi/180); // a is angle in radians
Sine = sin(a);  // this works properly now

Well..I changed the stuff and added a separate Radians Degrees Conversion part instead

Code:

void Program::Case6()
{
                           cout << "This is the radians-degrees/degrees-radians converter\n";
                           cout << "Choose - (M)Radians -> Degrees, (N)Degrees -> Radians\n";
                           cin >> g;
                           cin.ignore();
                           setcolor(13);
                           if (g[0] == 'M' ||g[0] == 'm')
                           {
                                   cout << "Enter radians - ";
                                   cin >> radians;
                                   degrees = radians * (180.0 / M_PI);
                                   cout << "Radians -> Degrees says " << degrees << " degrees" << endl;
                           }
                           else if (g[0] == 'N' ||g[0] == 'n')
                           {
                                   cout << "Enter degrees - ";
                                   cin >> degrees;
                                   radians = degrees * (M_PI / 180.0);
                                   cout << "Degrees -> Radians says " << radians << " radians" << endl;
                           }
                           setcolor(7);
}

But now I have problems with the program termination and case 7(trigonometry)
This is the program restart or quit code

Code:

void Program::RorQ() //Gives user the option to restart or quit
{
	C.exitRorQ = 1;
	while(C.exitRorQ == 1)
	{
	clrscr();
	cout << "(r) restart or (q) quit" <<endl;
	cout << ">";
			cin  >> C.rq[1];

			if (C.rq[1] == 'r')
					C.exitRorQ = 0;
			else if (C.rq[1] == 'q')
			{
				C.exitRorQ = 0;
				EXIT();
			}
			else
				{
                cout << "Thats not a choice... Please rechoose" << endl;
                }
	}
}

And this is the Case7

Code:

void Program::Case7()
{
                     setcolor(12);
                     cout << "Enter angle theta (radians) - ";
                     cin >> radians;
                     a = radians;
                     Sine = sin (a);
                     Cosine = cos (a);
                     Tangent = tan (a);
                     Arctan = atan (a);
                     Arccos = acos (a);
                     Arcsine = asin (a);
                     cout << "\nSine theta is " << Sine;
                     cout << "\nCos theta is " << Cosine;
                     cout << "\nTangent theta is " << Tangent;
                     cout << "\nInverse Sine(Arcsine) theta is " << Arcsine;
                     cout << "\nInverse Cos(Arccos) theta is " << Arccos;
                     cout << "\nInverse Tan(Arctan) theta is " << Arctan;
                     cout << "\n";
                     setcolor(7);
                     Sleep(3000);
}
.....
.....
case 7: 
                      OMGDOIT.Case7();
                      OMGDOIT.TerminationPrevention();
                      OMGDOIT.RorQ();      
                      break;

The restart or quit option works on all cases BUT this..If I try twice both r and q quit the program...

Code:

case 1:
                      OMGDOIT.Case1();
                      OMGDOIT.TerminationPrevention();
                      OMGDOIT.RorQ();
                      break;
                  case 2:
                      OMGDOIT.Case2();
                      OMGDOIT.TerminationPrevention();
                      OMGDOIT.RorQ();
                      break;
                  case 3:
                      OMGDOIT.Case3();
                      OMGDOIT.TerminationPrevention();
                      OMGDOIT.RorQ();
                      break;
                  case 4: 
                      OMGDOIT.Case4();
                      OMGDOIT.TerminationPrevention();
                      OMGDOIT.RorQ();
                      break;
                  case 5:
                      OMGDOIT.Case5(); 
                      OMGDOIT.TerminationPrevention();
                      OMGDOIT.RorQ();
                      break;  
                  case 6:
                      OMGDOIT.Case6();
                      OMGDOIT.TerminationPrevention();
                      OMGDOIT.RorQ();
                      break;
                  case 7: 
                      OMGDOIT.Case7();
                      OMGDOIT.TerminationPrevention();
                      OMGDOIT.RorQ();      
                  case 8:
                       C.exit = 0;  
                       break;  
                  default: 
                      cout << "Enter a number in the list\n";
                      break;

Code:

         default: 
                      cout << "Enter a number in the list\n";
                      break;
        }
        clrscr(); 
        }
              
        return 0;
}

This is what happens