附錄1

#pragma warning(disable:4996)
#include <cstdio>
#include <cmath>

#define MAXN 100
#define zero(x) (fabs(x)<1e-10)

struct mat{
    int n, m;
    double data[MAXN][MAXN];
};
double det(const mat &a){
    int i, j, k, sign = 0;
    double b[MAXN][MAXN], ret = 1
 
, t;
    if (a.n != a.m) return 0;
    for (i = 0; i<a.n; i++)
        for (j = 0; j<a.m; j++)
            b[i][j] = a.data[i][j];
    for (i = 0; i<a.n; i++){//行標+列標
        if (zero(b[i][i])){
            for (j = i + 1; j<a.n; j++)//行標
                if (!zero(b[j][i]))
                    break
 
;
            if (j == a.n) return 0;
            for (k = i; k<a.n; k++)//列標
                t = b[i][k], b[i][k] = b[j][k], b[j][k] = t;
            sign++;
        }
        ret *= b[i][i];
        for (k = i + 1; k<a.n; k++)//列標
            b[i][k] /= b[i][i];
        for (j = i + 1; j<a.n; j++)//行標
 

            for (k = i + 1; k<a.n; k++)//列標
                b[j][k] -= b[j][i] * b[i][k];
    }
    if (sign & 1) ret = -ret;
    return ret;
}
int main(){
    mat a;
    int i, j, n;
    while (scanf("%d", &n), n){
        a.n = a.m = n;
        for (i = 0; i<n; i++)
            for (j = 0; j<n; j++)
                scanf("%lf", &a.data[i][j]);
        printf("det a : %.2lf\n", det(a));
    }
    return 0;
}