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/*Gauss Seidel iterative method*/
#include<stdio.h>
#include<conio.h>
void main()
{
int c(float
*x,float *x1,int n,float e);
float mod(float
n),e;
printf("values of leading dia 0f the coefficient matrix should be
larger than others:\n");
printf("enter the value of tolerance:\n");
scanf("%f",&e);
int i,j,s,k,n;
printf("enter the max no of successive itterations to be performed
in any case:\n");
scanf("%d",&s);
printf("enter the no of unknowns:\n");
scanf("%d",&n);
float a[n][n+1];
printf("enter the elements of the augmented matrix
rowwise:\n");
for(i=0;i<n;i++)
{
for(j=0;j<n+1;j++)
scanf("%f",&a[i][j]);
}
float x[n],x1[n];
for(i=0;i<n;i++)
x[i]=x1[i]=0;
k=0;
do
{
for(i=0;i<n;i++)
x1[i]=x[i];
for(i=0;i<n;i++)
{
x[i]=a[i][n];
for(j=0;j<n;j++)
{
if(j!=i)
x[i]=x[i]-a[i][j]*x[j];
}
x[i]=x[i]/a[i][i];
}
k++;
}
while(k<=s
&& c(x,x1,n,e));
printf("the
solution is:\n");
for(i=0;i<n;i++)
printf("x%d=%f\n",i+1,x[i]);
getch();
}
int c(float *x,float *x1,int n,float e)
{
int i;
for(i=0;i<n;i++)
{
if(e<mod(*(x+i)-*(x1+i)))
return(1);
}
return(0);
}
float mod(float n)
{
if(n<=0)
return(-n);
else
return(n);
}
