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@YoungForest YoungForest/det.c
Created Dec 10, 2016

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求解矩阵对应行列式的值(C语言版)
#include <stdio.h>
#include <stdlib.h>
#define MAX 9 /*定义最大为9阶行列式*/
int Fun(int n, int a[MAX][MAX] ); /*函数声明*/
int main()
{
int n = 0; /*初始化阶数n*/
int i = 0, j = 0; /*i,j分别表示行与列*/
int a[MAX][MAX] = {{0}}; /*定义行列式*/
freopen("newin.txt", "r", stdin);
scanf("%d", &n); /*读入阶数*/
while ( n != 0) /*输入为0时退出程序*/
{
for ( i = 0; i < n; i++) /*此处2次循环将行列式存入数组中*/
{
for ( j = 0; j < n; j++)
scanf("%d", &a[i][j]);
}
printf("%d\n", Fun( n, a ) );
scanf("%d", &n);
}
return 0;
}
/*以下为计算行列式值的递归函数*/
int Fun( int n, int a[MAX][MAX] )
{
int b[MAX][MAX] = {{0}}; /*定义数组b并初始化*/
int i = 0, j = 0, sum = 0; /*i,j为行与列,sum为行列式的值*/
int x = 0, c = 0, p = 0; /*用x判断加与减,c,p为中间变量*/
if (n == 1)
return a[0][0];
for (i = 0; i < n; i++) /*此处大循环实现将余子式存入数组b中*/
{
for (c = 0; c < n - 1; c++)
{
for (j = 0; j < n - 1; j++)
{
if (c < i) { /*借助c判断每行的移动方法*/
p = 0; /*当p=0时,行列式只向左移,即消去对应的第一列的数*/
}
else { /*否则行列式左移后再上移*/
p = 1;
}
b[c][j] = a[c + p][j + 1];
}
}
if (i % 2 == 0) { /*i+j(此时j=0,故只考虑i)为偶数,加法预算*/
x = 1;
}
else { /*i+j为奇数,减法运算*/
x = (-1);
}
sum += a[i][0] * Fun(n - 1, b ) * x; /*计算行列式的值*/
}
return sum; /*将值返回*/
}
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