nyuan.cpp

数据结构作业

#include <stdio.h>
#include <stdlib.h>
int main()
{
 int n, i, j, k;
 double beishu, t = 0.0;
 double **a;
 printf("请输入未知量的个数:");
 scanf("%d", &n);
 printf("\n请输入系数矩阵和右端向量\n");
 //分配内存空间
 a = new double *[n];
 for (i =0 ; i < n; i++)
  a[i]= new double[n + 1];
 //输入数据
 for (i = 0; i < n; i++)
   for (j = 0; j <= n; j++)
    scanf("%lf", (*(a + i) + j));
   //用递归法解每个向量
 for(k = 0; k < n - 1; k++)
  for(i = k + 1; i < n; i++)
  {
  beishu = a[i][k]/a[k][k];
   for(j = k + 1; j < n; j++)
    a[i][j] = a[i][j] - beishu * a[k][j];
   a[i][n] = a[j - 1][n] - beishu* a[k][n];
  }
  a[n - 1][n] = a[n - 1][n]/a[n - 1][n - 1];
  //求解每个未知量
 for(i = n - 2; i >= 0; i--)
 {
  for (j = i + 1; j < n; j++)
   t+= a[i][j] * a[j][n];
  a[i][n] = (a[i][n] - t) / a[i][i];
 }
 //输出每个未知量
 for(i = 0; i < n; i++)
  printf("X%d = %lf\n", i + 1, a[i][n]);
  return 0;
}