matlab还没学精通，正好好久没写代码了，借此温习温习。

//Jacobi.cpp
#include "Jacobi.h"
#include <iostream>
#include <vector>
#include <stdlib.h>
using namespace std;
using std::vector;
vector<double> matrix_A;
vector<double> vector_b;

Jacobi::Jacobi()
{
	cout << "输入方阵维数：";
	cin >> order;
	std::cout << order << "阶矩阵构造成功" << endl; 
}



void Jacobi::input_matrix_A()
{	//由于数组在编译阶段就已经分配内存，维度必须是常量，故此处用向量来存储矩阵
	//初始化为order*order个int元素，没个元素都被初始化为0
	
	double elemt = 0;
	for (int i = 0; i <= order * order - 1; i++)
	{
		cout << "输入第" << i + 1 << "个元素" << endl;
		cin >> elemt;
		matrix_A.push_back(elemt);
	}
	pointer_A = &matrix_A[0];
	cout << "输入的矩阵为" << endl;
	output_matrix(pointer_A);
	
}

void Jacobi::input_vector_b()
{
	double element;
	for (int i = 0; i < order; i++)
	{
		cout << "请输入第" << i + 1 << "个b元素" << endl;
		cin >> element;
		vector_b.push_back(element);//构造成Ax-b=0
	}
	pointer_b = &vector_b[0];
	cout << "输入的列向量为" << endl;
	output_vector(pointer_b);
	
}
void Jacobi::structure_iterator()
{
	
	
	
	for (int i = 0; i <= order - 1; i++)
	{
		int denominator = pointer_A[i * order + i];
		pointer_b[i] = (pointer_b[i]) / denominator;
		for (int j = 0; j <= order - 1; j++)
		{
			pointer_A[i * order + j] = -(pointer_A[i * order + j]) / denominator;
		}
		pointer_A[i * order + i] = 0;
		
	}
	cout << "绝对误差限";
	double e;
	cin >> e;
	vector<double> vector_xk(order, 0);
	int n = 0,k=0;//n为满足绝对误差的解的个数,k为迭代次数
	do
	{
		n = 0;
		vector<double> vector_xk1(order, 0);//每次都初始化k+1
		
		for (int i = 0; i < order; i++)
		{
			for (int j = 0; j < order; j++)
			{
				vector_xk1[i] += (vector_xk[j] * pointer_A[i * order + j]);
			}
			vector_xk1[i] += pointer_b[i];
		}
		
		for (int i = 0; i < order; i++)
		{
			
			if (abs(vector_xk[i]-vector_xk1[i]) < e) 
			{
				n++;
			}

		}
		vector_xk = vector_xk1;
		k++;
		cout << "k=" << k << endl;
		output_vector(&vector_xk[0]);
	} while (n<order);

}
void Jacobi::output_matrix(double* p)
{
	double* pointer = p;
	for (int i = 0; i <= order - 1; i++)
	{
		for (int j = 0; j <= order - 1; j++)
		{
			cout << pointer[i * order + j] << "\t";
		}
		cout << endl;
	}

}

void Jacobi::output_vector(double* q)
{
	double* pointer = q;
	for (int i = 0; i < order; i++)
	{
		cout << pointer[i] << "\t";
	}
	cout << endl;
}```

```cpp
//Jacobi.h
#ifndef _JACOBI_H_
#define _JACOBI_H_

class Jacobi
{
public:
	void input_matrix_A(); //输入系数矩阵A
	void input_vector_b();//输入AX=b中的向量b
	void structure_iterator();//构造迭代公式
	void output_matrix(double* p);//输出矩阵
	void output_vector(double* q);//输出向量
	

	Jacobi();
private:
	
	double*  pointer_A = 0;//指向系数矩阵的指针
	double* pointer_b = 0;//指向b的指针
	int order = 0; //矩阵阶数
};

#endif