Jacobi itrative method

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#define ERROR 0.001

int main()
{

    int n,i,j,key,flag;
    float a[10][10],b[10],sum,x[10],x0[10],s=0;

    printf("enter the no of equations ");
    scanf("%d",&n);
    for(i=0;i<n;i++)
    {
        printf("enter coefficients of equation %d\t",i+1);
        for(j=0;j<n;j++)
            scanf("%f",&a[i][j]);
        printf("\nenter constant of equation %d\t",i+1);
        scanf("%f",&b[i]);
    }

    for(i=0;i<n;i++)
    {
        s=0;
        for(j=0;j<n;j++)
        {
            if(i!=j)
                s+=fabs(a[i][j]);
        }
        if(fabs(a[i][i])<s)
        {
            printf("error");
            exit(1);
        }

    }


    for(i=0;i<n;i++)
        x0[i]=b[i]/a[i][i];


flag=1;
while(flag)
{
    key=0;


    for(i=0;i<n;i++)
    {
        sum=b[i];

        for(j=0;j<n;j++)
        {
            if(j!=i)
            {
                sum=sum-(a[i][j]*x0[j]);
            }
        }

        x[i]=sum/a[i][i];

        if(key==0)
            if(fabs((x[i]-x0[i])/x[i])>ERROR)
                key=1;




    }

    if(key==1)
    {
            for(i=0;i<n;i++)
            {
                x0[i]=x[i];
            }

    }
    else
        flag=0;
}







    printf("the solutions for the variables are");

    for(i=0;i<n;i++)
    {
        printf("%f\t",x[i]);
    }
}