Displays Question Twice

[bettazproductions88]

So I am writing a program that can calculate the sin law for me, and i have written quite a few programs using the goto Redo; command, but I have never had it display my question twice. After I solve for one of the variables I just want it to go back to the main question, which variable I want to solve for.
My problem is that it displays the question twice, the first time it doesnt even give me a chance to type any input, than right below it, it displays the question again and this time it allows me to type something in.
How do I get rid of that first dud question?


#include <iostream.h>
#include <math.h>
#define NEWLINE '\n'
#define PI 3.14159265
using namespace std;

int main()
{
cout << " x y " << NEWLINE;
cout << " ----- = ----- " << NEWLINE;
cout << " sin(X) sin(Y) " << NEWLINE;
cout << NEWLINE << NEWLINE << NEWLINE;


Redo :

{
string input;
cout << NEWLINE << NEWLINE << NEWLINE;
cout << "Please Enter the Variable You Wish to Solve For : ";
getline(cin, input);
cout << NEWLINE << " ---------------------------------------------- " << NEWLINE;

if (input == "x")
{
double x, y, X, Y, A, B;
cout << "y = ";
cin >> y;
cout << NEWLINE << NEWLINE;

cout << "sin(X) = ";
cin >> X;
cout << NEWLINE << NEWLINE;

cout << "sin(Y) = ";
cin >> Y;
cout << NEWLINE << NEWLINE;

A = Y*(PI/180);
B = X*(PI/180);
x = (y*sin(B)/sin(A));

cout << "x = " << x;


}

else if (input == "y")
{
double A, B, X, Y, x, y;
cout << "x = ";
cin >> x;
cout << NEWLINE << NEWLINE;

cout << "sin(Y) = ";
cin >> Y;
cout << NEWLINE << NEWLINE;

cout << "sin(X) = ";
cin >> X;
cout << NEWLINE << NEWLINE;

A = Y*(PI/180);
B = X*(PI/180);
y = (x*sin(A)/sin(B));

cout << "y = " << y;


}

else if (input == "Sin(X)" || input == "sin(X)" || input == "SIN(X)" || input == "sin(x)")
{
double x, y, X, Y, A, B, C;
cout << "x = ";
cin >> x;
cout << NEWLINE << NEWLINE;

cout << "y = ";
cin >> y;
cout << NEWLINE << NEWLINE;

cout << "sin(Y) = ";
cin >> Y;
cout << NEWLINE << NEWLINE;

A = Y*(PI/180);
B = (x*sin(A)/y);
X = asin(B);
C = X*(180/PI);

cout << "Sin(X) = " << C;

}

else if (input == "Sin(Y)" || input == "sin(Y)" || input == "SIN(Y)" || input == "sin(x)")
{
double A, B, x, y, X, Y, C;
cout << "x = ";
cin >> x;
cout << NEWLINE << NEWLINE;

cout << "y = ";
cin >> y;
cout << NEWLINE << NEWLINE;

cout << "sin(X) = ";
cin >> X;
cout << NEWLINE << NEWLINE;

A = X*(PI/180);
B = (y*sin(A)/x);
Y = asin(B);
C = Y*(180/PI);

cout << "sin(Y) = " << C;
}


}
goto Redo;
return 0;

}

[vin]

You use getline and cin >> together which causes the problem.

You could replace getline(cin, input); with cin>>input;


or look up how to ignore the rest of the characters in the cin stream and place the command after all the elseif clauses.