Solve Quadratic Equations

Submitted on: 10/17/2000 3:36:40 PM

By:

Level: Beginner

User Rating: By 1 Users

Compatibility:C, C++ (general), Microsoft Visual C++, Borland C++, UNIX C++

Users have accessed this code 1668 times.

(About the author)

Check this cool Quadratic equation solving tool ! It even supports complex roots, all variables from 'a' to 'z'. Try this simple code and don't forget to vote for it.

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//**************************************

// Name: Solve Quadratic Equations

// Description:Check this cool Quadratic

// equation solving tool !

It even supports complex roots, all variables from 'a' to 'z'. try this simple code and don't forget to vote for it.

// By:

//This code is copyrighted and has// limited warranties.Please see http://

// www.1CPlusPlusStreet.com/xq/ASP/txtCodeI

// d.804/lngWId.3/qx/vb/scripts/ShowCode.ht

// m//for details.//**************************************

/* 220 lines - Updated 24th September 2000.

EQUATION SOLVERby ANKIT ROHATGI

~~~~~~~~ ~~~~~~~~~~~ ~~~~~~~

this is a program to solve simple quadratic equations.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Way of entering the equation (SYNTAX):-

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1) When the coefficient of a variable has been typed , a '*' has to

be further typed to indicate that the coefficient is multiplied

by the variable.

2) The equation input is ended by a '!'.

3) this WILL support complex answers.

4) All coefficients MUST be integers(Decimals not currently supported).

5) Type with CAPS LOCK OFF.

EXAMPLES :-

~~~~~~~~~~~

1) the equation 4xy+4x+1=0 has to be typed as:

4*x2+4*x+1*=0*!

2) the equation xy+4x+4=0 has to be typed as:

1*x2+4*x+4*=0*!

3) the equation xy+1=0 will be:

1*x2+0*x+1*=0*!

NOTE: The equations will be displayed on the screen (while typing) as:

~~~~ 4xy+4x+1=0!the character '*' will NOT be shown.

if it is displayed ,there is something wrong in your syntax.

THE 'i' in the complex answer means iota

#include

float getno(int fn=0);

void showsign(float no=0);

void main()

{ clrscr();

textcolor(14);

cprintf("This is the Equation solver by Ankit Rohatgi");

cout<<"\n";

textcolor(12);

cprintf("Press any key to input the equation");

cout<<"\n";

cprintf("GENERAL FORM 4xy+2x+3=0 ик 4*x2+2*x+3*=0*!");

cout<<"\a";

getch();

clrscr();

textcolor(14);

cprintf("Enter the Equation: \n");

textcolor(11);

char input='o',var,variable='x';

int a=0,c=0,c2,sign=1,pow,b;

float digit,A=0,B=0,C=0;

while(input!='!')

{ input=getche();

begin:

if(isdigit(input)||input=='-')

{ if(isdigit(input))

{ digit=getno((input-48));}

else

{ digit=(0-getno());

}

a=a+1;

if(a==1)

{A=digit;}

else if(a==2)

{B=digit;}

else if(a==3)

{C=digit;}

else if(a==4)

{C=C-digit;}

}

else if((input>='a')&&(input<='z'))

{ variable=input;

pow=getch();

if(pow=='2')

{ putch(253);

}

else if(pow=='!')

{ break;}

else

{ putch(pow);

input=pow;

goto begin;

}

textcolor(12);

cout<<"\nThe equation:\n "<

showsign(B);

cout<

showsign(C);

if(C>=0)

{cout<

else if(C<0)

{cout<<-C<<"=0";}

if((A!=0)&&(B!=0)&&(C!=0))

{

float bsqr=(B*B);

float fourac=(4*A*C);

if (fourac<=bsqr)

{ float delta=((B*B)-(4*A*C));

float sqrtdelta=sqrt(delta);

float ans1=((sqrtdelta-B)/(2*A));

float ans2=((sqrtdelta+B)/(2*A));

cout<<"\n"<

cout<<"\nor "<

}

else if(fourac>bsqr)

{ float delta=(fourac-bsqr);

float sqrtdelta=sqrt(delta);

cout<<"\n\n "<

}

if(A==0)

{ if(B!=0)

cout<<"\n "<

if((B==0)||(C==0))

cout<<"\n "<

goto finish;

}

if(B==0)

{ if(C!=0)

{ if(-C>0)

{ cout<<"\n "<

}

else

{ cout<<"\n "<

}

if(C==0)

{ cout<<"\n "<

}

goto finish;

}

if(C==0)

{ cout<<"\n "<

cout<<"\n "<

goto finish;

}

finish:

getch();

}

float getno(int fn)

{ char inchar='o';

int cnt=0,sign=1;

float noval=0,acval=0;

while(inchar!='*')

{ cnt++;

if(cnt==1)

{ inchar=getch();

if(isdigit(inchar))

{ sign=1;

noval=(fn*10)+(inchar-48);

putch(inchar);

}

if(isalpha(inchar))

{

}

if(inchar=='*')

{ noval=fn;goto maran;}

else

{ if(inchar=='+')

{ sign=1;

putch(inchar);

inchar=getche();

noval=(fn*10)+(inchar-48);

}

if(inchar=='-')

{ sign=0;

putch(inchar);

inchar=getche();

noval=(fn*10)+(inchar-48);

}

inchar=getch();

if(inchar=='*')

{ goto maran;

}

if(inchar!='*')

{ putch(inchar);

noval=(noval*10)+((inchar)-48);

}

maran:

cnt=0;

if(sign==0)

{ acval=-noval;

}

else if(sign==1)

{ acval=noval;

}

return(acval);

}

void showsign(float no)

{ if(no>=0)

{ putch(43);

}

else if(no<0)

{ putch(45);

}