[算法][雅可比迭代解方程组]

#include<iostream>
#include<cmath>
using namespace std;
#define maxn 50
int n;//维数
double a[maxn][maxn];//系数矩阵
double b[maxn];//b向量
double kc=0.000001;//精度控制常数
double x[maxn];//x向量
double y[maxn];
double e;
int N0;//最大迭代次数
//e=||x-(k+1)-x(k)||.inf.;当e<kc时计算终止;N0为最大迭代次数;
//t用于暂时存放Xi的原值,以便计算Xi-(k)-Xi(k-1)
int i,j,k;
bool read(){
    cout<<"|----------------------------------------|\n";
    cout<<"请输入矩阵规模n:= ";
    cin>>n;
    cout<<"请输入系数矩阵A:= \n";
    for(i=1;i<=n;i++)//输入a[][]
        for(j=1;j<=n;j++)
            cin>>a[i][j];
    cout<<"请输入b向量b:= \n";
    for(i=1;i<=n;i++)cin>>b[i];//输入b[]
    cout<<"请输入x向量的初始值x:= \n";
    for(i=1;i<=n;i++)cin>>x[i];//输入x[]初始值
    cout<<"请输入估计最大迭代次数N0:= \n";
    cin>>N0;
    return 1;
}
int main(){
    while(read()){
        for(k=1;k<=N0;k++){
            e=-1;
            for(i=1;i<=n;i++){
                y[i]=b[i];
                for(j=1;j<=n;j++)if(i!=j){
                    y[i]-=a[i][j]*x[j];
                }
                y[i]/=a[i][i];
                if(fabs(x[i]-y[i])>e)e=fabs(x[i]-y[i]);    
            }if(e<kc){//输出
                cout<<"|^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^|\n";
                cout<<"最大迭代次数 k = "<<k<<'\n';
                for(i=1;i<=n;i++)cout<<"x["<<i<<"]="<<y[i]<<'\n';
                goto END;
            }else{
                for(i=1;i<=n;i++)x[i]=y[i];    
            }
        }    
        cout<<"|^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^|\n";
        cout<<"失败\n";
        END:;
        cout<<"|----------------------------------------|\n\n";
    }return 0;
}
/*
6

4 -1 0 -1 0 0
-1 4 -1 0 -1 0
0 -1 4 -1 0 -1
-1 0 -1 4 -1 0
0 -1 0 -1 4 -1
0 0 -1 0 -1 4

0 5 -2 5 -2 6

0 0 0 0 0 0

50
*/