#include "stdafx.h"
#include "windows.h"
void Multi(int * left, int * right, int * result, int f1, int f2, int s1, int s2);

int main()
{
 int i, j;
 int a[4][3] = 
 { {1,2,3},
  {4,5,6},
  {7,8,9},
  {1,2,3}};
 int b[3][3] =
 { { 1,2,3 },
 { 4,5,6 },
 {7,8,9} };
 //c矩陣為a矩陣與b矩陣的乘積
 int c[4][3];
 //計(jì)算兩個(gè)矩陣相乘
 Multi(a[0], b[0],c[0], 4, 3, 3, 3);
 //輸出c矩陣
 for (i = 0; i < 4; i++)
 {
  for(j=0;j<3;j++)
   printf("%4d ", c[i][j]);
  printf("\n");
 }
 system("pause");
 return 0;
}

//矩陣相乘算法，最后四個(gè)參數(shù)是兩個(gè)相乘的矩陣的行數(shù)和列數(shù)
void Multi(int * left, int * right, int * result,int f1, int f2, int s1, int s2)
{
 //int a[f1][f2], b[s1][s2], c[f1][s2];
 //a[i][j]==a[i*f2+j]
 //由矩陣相乘，要求f2=s1，以下用f2
 for (int i = 0; i < f1; i++) //i表示第i行
 {
  for (int j = 0; j < s2; j++) //j表示第j列
  {
   result[i*f2 + j] = 0;  //在這里 result[i][j] = result[i*f2+j];
   for(int p=0;p<f2;p++)
   {
    result[i*f2 + j] +=left[i*f2+p]*right[p*f2+j];
   }
  }
 }
}