判断非齐次方程组是否有解 c++

#include <iostream>
using namespace std;

int main()
{
    double a[] ={2,2,2,
                3,2,4,
                1,3,9};

    double b[] = {1,0.5,2.5};
    double m =0;
    int n=3;

    for (int i = 0; i < n-1; i++)
    {
        for (int j = i + 1; j < n; j++)
        {
            m = a[j*n+i] / a[i*n+i];
            b[j] = b[j] - m * b[i];
            for (int k = i; k < n; k++)
            {
                a[j*n+k] = a[j*n+k] - m*a[i*n+k];
            }
        }
    }

    int deta=0;
    int detb=0;

    for (int i=0;i<n;i++)
    {
        if (b[i] == 0)
        {
            detb = i-1;
            break;
        }
    }
    if (detb ==0)
    {
        detb =2;
    }

    int tmp=0;
    for (int i=0;i<n;i++)
    {
        for (int j=0;j<n;j++)
        {
            if (a[i*n+j] == 0 )
            {
                tmp++;
            }
        }
        if (tmp == n)
        {
            deta = i-1;
            break;
        }
        tmp =0;
    }

    if (tmp ==0)
    {
        deta=2;
    }
    
    for (int i=0;i<n;i++)
    {
        for (int j=0;j<n;j++)
        {
            cout<<a[i*n+j]<<"";
        }
        cout<<endl;
    }

    cout<<endl;
    for (int i=0;i<n;i++)
    {
        cout<<b[i]<<"";
    }
    cout<<endl;
    cout<<deta<<""<<detb<<endl;

    if (deta < detb)
    {
        cout<<"no exit solution"<<endl;
    }
    else
    {
        cout<<"exit solution"<<endl;
    }

    system("pause");
    return 0;
}