MatrixMultiplicstion.c

//Matrix multiplication
//matrix1: m x s
//matrix2: s x n

#include <stdio.h>

void matrixInput(int m, int n, float (*a)[n]);

void MatrixMultiply(int m, int s, int n,
    float (*matrix1)[s], float (*matrix2)[n], 
    float (*matrixResult)[n]);

int main(void)
{
  int i, j, k, m, s, n;

  printf("Please input the m of matrix1\n");
  scanf("%d", &m);

  printf("Please input the s of matrix1\n");
  scanf("%d", &s);

  printf("Please input the n of matrix2\n");
  scanf("%d", &n);

  float matrix1[m][s], matrix2[s][n], matrixResult[m][n];
  printf("Please input elements of matrix1:(%d*%d)\n", m, s);
  matrixInput(m, s, matrix1);

  printf("Please input elements of matrix2:(%d*%d)\n", s, n);
  matrixInput(s, n, matrix2);

  MatrixMultiply(m, s, n, matrix1, matrix2, matrixResult);

  printf("the result:\n");
  for (i = 0; i < m; ++i)
  {
    for (j = 0; j < n; ++j)
    {
      printf("%f ", matrixResult[i][j]);
    }

    printf("\n");
  }

  return 0;
}

void MatrixMultiply(int m, int s, int n,
    float (*matrix1)[s], float (*matrix2)[n], 
    float (*matrixResult)[n])
{
  int i, j, k;

  for (i = 0; i < m; ++i)
  {
    for (j = 0; j < n; ++j)
    {
      for (k = 0, matrixResult[i][j] = 0; k < s; ++k)
      {
	matrixResult[i][j] += matrix1[i][k] * matrix2[k][j];
      }
    }
  }
}

void matrixInput(int m, int n, float (*a)[n])
{
  int i, j;

  for (i = 0; i < m; ++i)
  {
    for (j = 0; j < n; ++j)
    {
      scanf("%f", &a[i][j]);
    }
  }
}