Thread: parse error before else

I think the illegal part is in bold here...

Originally posted by sdchem
Hi. I am trying to program a short algebra routine to give me the answers to a quadratic function. The compiler says there are "parse errors before 'else'" on lines 35, 41 and 45. Somebody probably knows why. Thanx

code:

Code:

#include <iostream.h>
#include <stdlib.h>

int main()
{
		//Solve a quadratic equation for x.
		cout<<"Solve a*x^2 + b*x + c = 0, for x."<<endl;
		cout<<""<<endl;
		cout<<""<<endl;
		//declare variables
		double a,b,c,delta,x,x1r,x2r,real,imag;
		cout<<""<<endl;
		cout<<"Please type in a."<<endl;
		cin>>a;
		cout<<"Please type in b."<<endl;
		cin>>b;
		cout<<"Please type in c."<<endl;
		cin>>c;
		cout<<""<<endl;
		cout<<""<<endl;
		cout<<"The value for a is "<<a<<".  The value for b is "<<b<<".  The value for c is "<<c<<"."<<endl;
		cout<<""<<endl;
		cout<<""<<endl;
        system("PAUSE");
                        if(a==0)
                                if(b==0)
                                        if(c==0)
                                        cout<<"Indefinite equation."<<endl;
                                        else
                                        cout<<"Impossible equation."<<endl;
                                else
                                x=-c/b;
                                cout<<"One real solution x="<<x<<"."<<endl;
                        else
                        delta=b^2-4*a*c;
                                if(delta>0)
                                x1r=(-b+sqrt(delta))/(2*a);
                                x2r=(-b-sqrt(delta))/(2*a);
                                cout<<"Two real solutions x1="<<x1r<<"x2="<<x2r<<"."<<endl;
                                else
                                    if(delta=0)
                                    x=b/(2*a);
                                    cout<<"One double solution x="<<x<<"."<<endl;
                                    else
                                    real=-b/(2*a)
                                    imag=sqrt(-delta)/(2*a);
                                    cout<<"Two complex solutions x1="<<real<<" + "<<imag<<"i and x2="<<real<<" - "<<imag<<"i."<<endl;
        return 0;

}

You put an else where there is no if.

the solution is to use curly brackets around the code that you want to group into an if statement