DaniWeb Forum Index > Software Development > C

Quadratic Formula

Please support our C advertiser: Programming Forums - DaniWeb Sister Site

Thread Solved

•

Join Date: Jul 2008

Posts: 38

Reputation: plike922 is an unknown quantity at this point

Solved Threads: 0

plike922

Offline

Light Poster

Quadratic Formula

Jul 24th, 2008

I am trying to create a program that gets the solution of a quadratic formula, but i keep getting an error and i cant figure it out.

1>quad.cpp(14) : error C2440: '=' : cannot convert from 'int (__cdecl *)(void)' to 'int'
1> There is no context in which this conversion is possible
1>quad.cpp(16) : error C2440: '=' : cannot convert from 'int (__cdecl *)(void)' to 'int'
1> There is no context in which this conversion is possible
1>quad.cpp(18) : error C2440: '=' : cannot convert from 'int (__cdecl *)(void)' to 'int'
1> There is no context in which this conversion is possible
1>quad - 3 error(s), 21 warning(s)

Here is the program

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
#include <iostream>
#include <stdio.h>
#include "simpio.h"
#include "strlib.h"
#include "random.h"
#include "math.h"
using namespace std;
 
int main()
{
	int a, b, c, x, y, z;
 
	printf("Enter A: ");
	a = GetInteger;
	printf("Enter B: ");
	b = GetInteger;
	printf("Enter c: ");
	c = GetInteger;
z = (b*b-4*a*c)
x = ((-b - z)/(2*a));
y = ((-b + z)/(2*a));
 
if (x = y)
{
	printf("There is one solution: %d", x);
}
else if (x != y)
{
	printf("There are two solutions: %d and %d", x, y);
}
else
{
	printf("There are no solutions");
}
system("pause");
}
#include <iostream>
#include <stdio.h>
#include "simpio.h"
#include "strlib.h"
#include "random.h"
#include "math.h"
using namespace std;

int main()
{
	int a, b, c, x, y, z;

	printf("Enter A: ");
	a = GetInteger;
	printf("Enter B: ");
	b = GetInteger;
	printf("Enter c: ");
	c = GetInteger;
z = (b*b-4*a*c)
x = ((-b - z)/(2*a));
y = ((-b + z)/(2*a));

if (x = y)
{
	printf("There is one solution: %d", x);
}
else if (x != y)
{
	printf("There are two solutions: %d and %d", x, y);
}
else
{
	printf("There are no solutions");
}
system("pause");
}

_________________________
||||||||||[][][]|||||||||||||||||||
|||||||||||||||____|
||||||||||
||||||||||

•

Join Date: Oct 2007

Posts: 280

Reputation: joshmo is an unknown quantity at this point

Solved Threads: 19

joshmo

Offline

Posting Whiz in Training

Re: Quadratic Formula

Jul 24th, 2008

There could be a possibility that if "GetInteger" is a function it is not of integer type. Otherwise if "GetInteger" is not a function then it is not declared

•

Join Date: Dec 2006

Posts: 251

Reputation: ssharish2005 is on a distinguished road

Solved Threads: 20

ssharish2005 ssharish2005 is offline

Offline

Posting Whiz in Training

Re: Quadratic Formula

Jul 24th, 2008

pLike, you should really consider looking at on how to indentent you code first. Well the error message you get there is basiclly specifying that GetInteger cannot be assigned to the interger. It donst know what the RHS is? Seems to me like it is function or is it macro if there was no brackets ????

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
#include <stdio.h>
 
int main()
{
    int a, b, c, x, y, z;
 
    printf("Enter A: ");
    a = GetInteger();
 
    printf("Enter B: ");
    b = GetInteger();
 
    printf("Enter c: ");
    c = GetInteger();
 
    z = ( b * b - 4 * a * c );
    x = ( ( -b - z ) / ( 2 * a ) );
    y = ( ( -b + z ) / ( 2 * a ) );
 
    if ( x == y )
    	printf("There is one solution: %d", x);
    else if ( x != y )
    	printf("There are two solutions: %d and %d", x, y);
    else
    	printf("There are no solutions");
 
    system("pause");
    return 0;
}
#include <stdio.h>

int main()
{
    int a, b, c, x, y, z;

    printf("Enter A: ");
    a = GetInteger();

    printf("Enter B: ");
    b = GetInteger();

    printf("Enter c: ");
    c = GetInteger();

    z = ( b * b - 4 * a * c );
    x = ( ( -b - z ) / ( 2 * a ) );
    y = ( ( -b + z ) / ( 2 * a ) );

    if ( x == y )
    	printf("There is one solution: %d", x);
    else if ( x != y )
    	printf("There are two solutions: %d and %d", x, y);
    else
    	printf("There are no solutions");

    system("pause");
    return 0;
}

And the in the if statment, there two two equals opeator not the assignment operator if ( x == y )
ssharish

Last edited by ssharish2005; Jul 24th, 2008 at 3:50 pm.

•

Join Date: Jul 2008

Posts: 38

Reputation: plike922 is an unknown quantity at this point

Solved Threads: 0

plike922

Offline

Light Poster

Re: Quadratic Formula

Jul 25th, 2008

Ok... Thanks that solved that, but i have a new problem, i can't get the decimals with the number here is the improved program.

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
#include <iostream>
#include <stdio.h>
#include "simpio.h"
#include "strlib.h"
#include "random.h"
#include "math.h"
using namespace std;
 
int main()
{
	int a, b, c, x, y, d;
 
	printf("Enter A: ");
	a = GetInteger();
 
	printf("Enter B: ");
	b = GetInteger();
 
	printf("Enter C: ");
	c = GetInteger();
 
	d = (b*b-4*a*c)^(1/2);
	x = ((-b - d)/(2.0*a));
	y = ((-b + d)/(2.0*a));
 
	if (x == y)
		printf("There is one solution: %d\n", x);
	else if (x != y)
		printf("There are two solutions: %d and %d\n", x, y);
	else if (d <= 0)
		printf("There are no solutions.\n");
	else
		printf("There are no solutions.\n");
 
	system("pause");
	return 0;
}
#include <iostream>
#include <stdio.h>
#include "simpio.h"
#include "strlib.h"
#include "random.h"
#include "math.h"
using namespace std;

int main()
{
	int a, b, c, x, y, d;

	printf("Enter A: ");
	a = GetInteger();

	printf("Enter B: ");
	b = GetInteger();

	printf("Enter C: ");
	c = GetInteger();

	d = (b*b-4*a*c)^(1/2);
	x = ((-b - d)/(2.0*a));
	y = ((-b + d)/(2.0*a));

	if (x == y)
		printf("There is one solution: %d\n", x);
	else if (x != y)
		printf("There are two solutions: %d and %d\n", x, y);
	else if (d <= 0)
		printf("There are no solutions.\n");
	else
		printf("There are no solutions.\n");

	system("pause");
	return 0;
}

_________________________
||||||||||[][][]|||||||||||||||||||
|||||||||||||||____|
||||||||||
||||||||||

•

Join Date: Jan 2008

Posts: 3,836

Reputation: VernonDozier has a reputation beyond repute

Solved Threads: 503

VernonDozier VernonDozier is offline

Offline

Senior Poster

Re: Quadratic Formula

Jul 25th, 2008

iostream isn't in C. I think you have quotes where you want <> in your #include for math.h, and you can't use "using namespace std" in C. Maybe you're not using a C compiler.

The problem with the decimals is that you've declared all of your variables as integers and integers can't hold decimals. Try declaring x, y, d as doubles or floats.

I'm also suspicious of this line:

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
d = (b*b-4*a*c)^(1/2);
d = (b*b-4*a*c)^(1/2);

^ is the bitwise XOR operator and I think (1 / 2) is going to be 0 due to integer division.

Last edited by VernonDozier; Jul 25th, 2008 at 1:01 am.

•

Join Date: May 2008

Posts: 376

Reputation: Clockowl is on a distinguished road

Solved Threads: 27

Clockowl

Offline

Posting Whiz

Re: Quadratic Formula

Jul 25th, 2008

You're getting C++ errors. C++ is a lot stricter. Try using a C compiler.

•

Join Date: Jan 2008

Posts: 3,836

Reputation: VernonDozier has a reputation beyond repute

Solved Threads: 503

VernonDozier VernonDozier is offline

Offline

Senior Poster

Re: Quadratic Formula

Jul 25th, 2008

•

Originally Posted by Clockowl

You're getting C++ errors. C++ is a lot stricter. Try using a C compiler.

You have that backwards. These lines:

Help with Code Tags

C Syntax (Toggle Plain Text)

#include <iostream>
using namespace std;

are fine with a C++ compiler, but cannot be used with a C compiler.

•

Join Date: May 2008

Posts: 376

Reputation: Clockowl is on a distinguished road

Solved Threads: 27

Clockowl

Offline

Posting Whiz

Re: Quadratic Formula

Jul 25th, 2008

"cannot convert from" is a C++ (and in general, OOP) only error afaik.

Last edited by Clockowl; Jul 25th, 2008 at 11:16 am.

•

Join Date: Sep 2004

Posts: 7,823

Reputation: Narue has a reputation beyond repute

Solved Threads: 748

Narue

Offline

Senior Bitch

Re: Quadratic Formula

Jul 25th, 2008

>You're getting C++ errors. C++ is a lot stricter. Try using a C compiler.
So your advice is to ignore the warning and let the problem silently continue. Brilliant.

>"cannot convert from" is a C++ (and in general, OOP) only error afaik.
You get it in C as well if you do something stupid...just like C++.

Last edited by Narue; Jul 25th, 2008 at 11:25 am.

New members chased away this month: 3

•

Join Date: Jan 2008

Posts: 3,836

Reputation: VernonDozier has a reputation beyond repute

Solved Threads: 503

VernonDozier VernonDozier is offline

Offline

Senior Poster

Re: Quadratic Formula

#10

Jul 25th, 2008

•

Originally Posted by Clockowl

"cannot convert from" is a C++ (and in general, OOP) only error afaik.

Ah, OK, you are referring to these lines, perhaps?

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
x = ((-b - d)/(2.0*a));
y = ((-b + d)/(2.0*a));
x = ((-b - d)/(2.0*a));
y = ((-b + d)/(2.0*a));

I get a warning in C++ (not an error) which says "Warning: Converting from 'int' to 'double'". I don't get the "cannot convert from" error. It converts it using the C++ compiler, but throws out the warning and it's the programmer's decision about whether to pay attention to the warning or not. Maybe it's an error instead of a warning if you have certain compiler flags. In this case, it's a warning that the OP should definitely pay attention to and not ignore. You're right, though, given that this is the C forum and hence the OP should be using a C compiler, there will be no warning whatsoever on these conversions, or at least there wasn't on my C compiler.