#include <stdio.h>
#include <math.h>
#include <malloc.h>

void Jacobidiedai(int n, double *a, double *b,double *x)
{
    int i,j;
    double *x0,m=0,eps=0;
    x0= (double *) malloc(n*sizeof(double));
    for(i=0;i<n;i++)
        x0[i]=x[i];
    while(1)
    {
        for(i=0;i<n;i++)
        {
            for(j=0;j<n;j++)
                m+=a[i*n+j]*x0[j];
            m-=a[i*n+i]*x0[i];
            x[i]=(b[i]-m)/a[i*n+i];
            m=0;
        }
        for(i=0;i<n;i++)
        {
            if(eps<fabs(x[i]-x0[i]))
                eps=fabs(x[i]-x0[i]);
        }
        if(eps<1e-3)
            return;
        for(i=0;i<n;i++)
            x0[i]=x[i];
    }
    free(x0);
}

void main()
{
    int i,j,n;
    double *a;
    double *b;
    double *x;
   
    printf("please enter n\n");
    scanf("%d",&n);
    a = (double *)malloc(sizeof(double)*n*n);
    b = (double *)malloc(sizeof(double)*n);
    x = (double *)malloc(sizeof(double)*n);
    memset(x,0,n);
    printf("please enter a[i][j]\n");
    for (i=0;i<n*n;i++) scanf("%f",&a[i]);
    printf("please enter b[j]\n");
    for (j=0;j<n;j++) scanf("%f",&b[j]);
    Jacobidiedai(n,a,b,x);
    for(i=0;i<n;i++)
        printf("x[%d]=%f\n",i,x[i]);
}

这个公式早忘了！

。。。

。。。