#include <stdio.h>
#include <math.h>

int main()
{
	float a, b, c, d;
	float root1, root2;
	float cont = 1;

	do {
		printf("Solving quadratic equation: ax^2+bx+c=0\n");
		printf("a = ");
		scanf("%f", &a);
		
		while (a == 0)
		{
			printf("a can't be equal to 0\n");
			printf("a = ");
        	        scanf("%f", &a);
		}
		if ( a != 0 )
		{		
			printf("b = ");
			scanf("%f", &b);
			printf("c = ");
			scanf("%f", &c);
		}
	
		d = (b * b) - (4 * a * c);
	
		if ( d == 0 )
		{
			root1 = -b / ( 2 * a );
			printf("There is an equal root.\n");
			printf("It is %f.\n\n", root1);
		}
		else if ( d > 0 )
		{
			root1 = (-b + sqrt(d)) / (2 * a);
			root2 = (-b - sqrt(d)) / (2 * a);
			printf("There are two real roots.\n");
			printf("They are %f and %f.\n\n", root1, root2);
		}	
		else
		{
			printf("No real root\n\n");
		}


		do{
			printf("Continue (yes=1/no=0)?\n");		/* Ask Continue */
			scanf("%f", &cont);
			printf("\n");
		} while (cont != 0 && cont != 1);

	} while (cont == 1);
	
	return 0;
}