C Program for False Position Method

/*False Position Method*/

#include<stdio.h>

#include<conio.h>

#include<alloc.h>

#include<math.h>

#include<process.h>

float **e,n;

float value(float);

void main()

{

float x,v,v1,v2,xr,xu,xl,xo=0,ea,es;

int i,p,it=50;

char ch;

clrscr();



printf("Enter degree\n");

scanf("%f",&n);

e=(float**)malloc(((n+1)*2)*4);

puts("------------------------------------------");

printf("Enter coeff.in decreasing order of degree\n");

for(i=0,p=n;i<=n;i++,p--)

{

scanf("%f",&e[i][0]);

e[i][1]=p;

}

puts("------------------------------------------");

printf("Enter value of xl and xu\n");

scanf("%f %f",&xl,&xu);

puts("------------------------------------------");

puts("What would you like to Enter\nEs or Number of significant fig or Iteration .=>E/S/I");

ch=getche();

if(ch=='E'||ch=='e')

{

printf("\nEnter value of Es\n");

scanf("%f",&es);

}

else if(ch=='i'||ch=='I')

{printf("Enter no. of Iteration"); scanf("%d",&it);

}

else

{

printf("\nEnter no. of sig. fig\n");

scanf("%d",&p);

es=0.5*pow(10,(2-p));

}

puts("-------------------------------------------");

i=0;

printf("Iteration\tX\t\tEa");

while(1)

{

i++; /*-- Iteration number --*/

v1=value(xl);

v2=value(xu);

if(v1*v2>=0)

{

printf("Invalid Value of xl and xu");

getch();

exit(0);

}

xr=xu-(v2*(xl-xu)/(v1-v2));

ea=(xr-xo)*100/xr;

if(ea<0)

ea=ea*-1;

v=value(xr);

if(v==0||ea<es)

{

printf("\n%3d\t\t%6.5f\t\t%5.4f",i,xr,ea);

puts("\n-----------------------------------------------");

getch();

exit(0);

}

printf("\n%3d\t\t%6.5f\t\t%5.4f",i,xr,ea);

if(v1*v<0)

xu=xr;

else

xl=xr;

xo=xr; }

}

float value(float x)

{

int i;

float s=0;

for(i=0;i<=n;i++)

{

s=s+e[i][0]*pow(x,e[i][1]);

}

return s;

}







Output Of Program:-




First:-

Enter degree

2

------------------------------------------

Enter coeff.in decreasing order of degree

-0.4 2.2 4.7

------------------------------------------

Enter value of xl and xu

5 10

------------------------------------------

What would you like to Enter

Es or Number of significant fig.or Iteration=>E/S/I

e

Enter value of Es

1

-------------------------------------------

Iteration X Ea

1 6.50000 100.0000

2 6.97727 6.8404

3 7.10297 1.7696

4 7.13435 0.4399

-----------------------------------------------































Second:-

Enter degree

2

------------------------------------------

Enter coeff.in decreasing order of degree

-0.5 2.5 4.5

------------------------------------------

Enter value of xl and xu

5 10

------------------------------------------




What would you like to Enter

Es or Number of significant fig.or Iteration=>E/S/I

I

Enter no. of Iteration

4

-------------------------------------------

Iteration X Ea

1 5.90000 100.0000

2 6.23853 5.4265

3 6.35184 1.7838

4 6.38825 0.5700

-----------------------------------------------