收集的C语言算法程序

******************************************************************************
                                                   inf.txt                                                             
                                               0  0  0  0  0                                                            
                                               0  -1  2  -2  -1                                                         
                                               0  3  -1  4  7                                                           
                                               0  2  -3  -2  0 
                ******************************************************************************/
#include<fstream>
#include<iostream>
#include<cmath>
int count=0;
using namespace std;
#define N 3
#define w 100
bool flag=true;
void main()
{float a[N+1][N+2];
int i,j;
ifstream infile("inf.txt",ios::in);
if(!infile)
{
 cerr<<"错误：文件“inf.txt”无法打开！";
 exit(1);
}
for(i=0;i<N+1;i++)
{
 for(j=0;j<N+2;j++)
 {
  infile>>a[i][j];
 }
}
infile.close();
float x[N+1]={0};
 //cout<<a[3][1];
float x1[N+1];//x1[N+1]表示新得的方程组的解
//for(i=1;i<=N;i++)
//x1[i]=a[i][N+1];
 float max=0;
while(flag)
{
 count++;
 for(i=1;i<=N;i++)
 {  x1[i]=a[i][N+1];
  for(j=1;j<=i-1;j++)
  {
   x1[i]-=a[i][j]*x[j];
   
  }
  for(j=i+1;j<=N;j++)
  {
   x1[i]-=a[i][j]*x[j];
   
  }
  x1[i]*=w;
 }
 float max=0;
 for(i=0;i<=N;i++)
 {
  if(max<fabs(x1[i]-x[i]))
  {
   max=fabs(x1[i]-x[i]);
  }
 }
 if(max<0.01)
 break;
 for(int k=1;k<=N;k++)
 {
  x[k]=x1[k];
 }
 if(count==100000)
 {
  cout<<"在"<<count<<"次迭代中未能得到所要的结果，程序已被中止!"<<endl;
  return;
 }
}
 
cout<<"经计算知该方程组的解为:\n"<<"x1="<<x[1]<<ends<<"x2="<<x[2]<<ends<<"x3="<<x[3]<<endl;

}