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#include <iostream>
#include <string>
#include <vector>
#include <iomanip>
using namespace std;
const int n=3; //设置方程组的维
float a[n][n]={10,-1,-2,-1,10,-2,-1,-1,5},x[n]={0,0,0},b[n]={7.2,8.3,4.2};
void input_data() //输入方程组的相关数据
{
cout<<"输入方程组的系数矩阵a["<<n<<"]["<<n<<"]:"<<endl;
for(int i=0;i<n;i++)
for(int j=0;j<n;j++)
cin>>a[i][j];
cout<<"输入x[1,...,"<<n<<"]的初值:"<<endl;
for(i=0;i<n;i++)
cin>>x[i];
cout<<"输入b[1,...,"<<n<<"]的初值:"<<endl;
for(i=0;i<n;i++)
cin>>b[i];
}
void output_equation() //输出方程组
{
for(int i=0;i<n;i++)
{
for(int j=0;j<n;j++)
{
if(j>0&&a[i][j]>0)
cout<<"+";
cout<<a[i][j]<<" x["<<j+1<<"] ";
}
cout<<"="<<b[i]<<endl;
}
}
void main ()
{
//input_data();
int counter; //设置计算时迭代的次数
cout<<"输入迭代的次数"<<endl;
cin>>counter;
system("cls");
output_equation();
int k=0,i=0; //k用来统计迭代的次数;i用来表示x的序列
float m_num1; //m_x用来保存x的原先值;m_num1用来计算j!=i的数据之和
cout<<endl;
cout<<"k\t";
for(int j=0;j<n;j++)
cout<<"x["<<j+1<<"]\t\t\t";
cout<<endl;
cout<<k<<"\t";
k++;
cout << setiosflags(ios::fixed); //和下一句结合起来用来设定小数位的位数
cout << setprecision(10);
for(j=0;j<n;j++)
cout<<x[j]<<"\t\t";
cout<<endl;
do
{
m_num1=0;
for(j=0;j<n;j++)
{
if(j!=i)
m_num1=m_num1+a[i][j]*x[j];
}
x[i]=(b[i]-m_num1)/a[i][i];
if(i<n-1)
i++;
else
{
cout<<k<<"\t";
for(j=0;j<n;j++)
cout<<x[j]<<"\t\t";
cout<<endl;
i=0;
k++;
};
}while(k<=counter);
}
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