线性代数四阶方程运算

计算线性代数四阶方程一般很麻烦，用代码解决就很容易

头文件

#pragma once
#include<iostream>
using namespace std;

class calculator
{
public:
  void display();//显示界面
  void close();//关闭程序
  void four();//计算四阶行列式
  int text01(int tempnumber[3][3]);
};

cpp文件

#include"线性代数计算器.h"

void calculator::display()
{
  cout << "*******************线性代数**********************" << endl;
  cout << "*****************0.关闭程序**********************" << endl;
  cout << "**************1.四阶行列式计算*******************" << endl;

}
void calculator::close()
{
  cout << "欢迎下次使用" << endl;
  exit(0);
}
void calculator::four()
{
  int number[4][4];
  for (int i = 0; i < 4; i++)
  {
    cout << "请输入第" << i + 1 << "行数:" << endl;
    cin >> number[i][0] >> number[i][1] >> number[i][2] >> number[i][3];
  }
  int tempnumber[3][3];
  int total[4];
  //1
  for (int i = 0; i < 3; i++)
  {
    for (int k = 0; k < 3; k++)
    {
      tempnumber[i][k] = number[i + 1][k + 1];
    }
  }
  
  int temp1 = text01(tempnumber);
  total[0] = temp1 * number[0][0];
  //2
  for (int i = 0; i < 3; i++)
  {
    for (int k = 0; k < 3; k++)
    {
      int g = k + 1;
      if (k == 0)
      {
        g = k;
      }
      tempnumber[i][k] = number[i + 1][g];
    }
  }
  int temp2 = text01(tempnumber);
  total[1] = -temp2 * number[0][1];
  //3
  for (int i = 0; i < 3; i++)
  {
    for (int k = 0; k < 3; k++)
    {
      int g = k;
      if (k == 2)
      {
        g = k + 1;
      }
      tempnumber[i][k] = number[i + 1][g];
    }
  }
  int temp3 = text01(tempnumber);
  total[2] = temp3 * number[0][2];

  //4
  for (int i = 0; i < 3; i++)
  {
    for (int k = 0; k < 3; k++)
    {
      tempnumber[i][k] = number[i + 1][k];
    }
  }
  int temp4 = text01(tempnumber);
  total[3] = -temp4 * number[0][3];
  int total2 = total[0] + total[1] + total[2] + total[3];
  cout << "结果为:" << total2 << endl;
}
int calculator::text01(int tempnumber[3][3])
{
  int total2[3];
  total2[0] = tempnumber[0][0] * (tempnumber[1][1] * tempnumber[2][2] - tempnumber[1][2] * tempnumber[2][1]);
  total2[1] = -tempnumber[0][1] * (tempnumber[1][0] * tempnumber[2][2] - tempnumber[1][2] * tempnumber[2][0]);
  total2[2] = tempnumber[0][2] * (tempnumber[1][0] * tempnumber[2][1] - tempnumber[1][1] * tempnumber[2][0]);
  return (total2[0] + total2[1] + total2[2]);
}

主函数文件

#include"线性代数计算器.h"


int main()
{
  calculator cal;
  int select = 0;
  while (true)
  {
    cal.display();
    cout << "请输入数字进行操作:";
    cin >> select;
    switch (select)
    {
    case 0:
      cal.close();
      break;
    case 1:
      cal.four();
      break;
    }
    system("pause");
    system("cls");
  }
  return 0;
}

效果