Implementation of Simpson one third rule in C.

Here is the code..

// TO IMPLEMENT INTEGRATION BY SIMPSON(1/3) RULE

#include<stdio.h>

float value(float );

void main()

{float a,b,v,z,m,h,*x,*y;

int i,k;

printf( "SIMPSON 1/3 RULE\n");

printf("fx=(1\(1+x^2))\n");

printf("Enter lower,upper limits of integrtion\t");

scanf("%f%f",&a,&b);

printf("\nEnter the no of parts of interval(k)\t");

scanf("%d",&k);

x=(float *)malloc(sizeof(float)*(k+1));

y=(float *)malloc(sizeof(float)*(k+1));

x[0]=a;

y[0]=value(x[0]);

for(i=1;i<=k;i++)

{x[i]=x[i-1]+(float)(b/k);

y[i]= value(x[i]);

}for(i=0;i<=k;i++)

printf("|x=%f,y=%f|\n",*(x+i),*(y+i));

z=0;

h=((b-a)/k);

for(i=1;i<k;)

{z=z+y[i];

i=i+2;

}m=0;

for(i=2;i<k;)

{m=m+y[i];

i=i+2;

}

v=((h/3.0)*(y[0]+y[k]+4*z+2*m));

printf("Value of integration is %f \t",v);

free(x);

free(y);

}

float value(float w)

{return(1/(1+(w*w)));

}

For Turbo C users.

// TO IMPLEMENT INTEGRATION BY SIMPSON(1/3) RULE

#include<stdio.h>

#include<conio.h>

#include<alloc.h>

float value(float );

void main()

{float a,b,v,z,m,h,*x,*y;

int i,k;

clrscr();

printf( "SIMPSON 1/3 RULE\n");

printf("fx=(1\(1+x^2))\n");

printf("Enter lower,upper limits of integrtion\t");

scanf("%f%f",&a,&b);

printf("\nEnter the no of parts of interval(k)\t");

scanf("%d",&k);

x=(float *)malloc(sizeof(float)*(k+1));

y=(float *)malloc(sizeof(float)*(k+1));

x[0]=a;

y[0]=value(x[0]);

for(i=1;i<=k;i++)

{x[i]=x[i-1]+(float)(b/k);

y[i]= value(x[i]);

}for(i=0;i<=k;i++)

printf("|x=%f,y=%f|\n",*(x+i),*(y+i));

z=0;

h=((b-a)/k);

for(i=1;i<k;)

{z=z+y[i];

i=i+2;

}m=0;

for(i=2;i<k;)

{m=m+y[i];

i=i+2;

}

v=((h/3.0)*(y[0]+y[k]+4*z+2*m));

printf("Value of integration is %f \t",v);

free(x);

free(y);

getch();

}

float value(float w)

{return(1/(1+(w*w)));

}