#include <stdio.h>
void array_mul(int (*x)[2],int (*y)[2],int (*ans)[2]){
  int i,j,k;
  for(i=0;i<2;i++){
    for(j=0;j<2;j++){
      ans[i][j]=0;
      for(k=0;k<2;k++){
        ans[i][j] += x[i][k] * y[k][j];
      }
    }
  }
}
int main(void){
  int x[2][2]={1,2,3,4};
  int y[2][2]={1,2,3,4};
  int ans[2][2];
  int i,j;
  array_mul(x,y,ans);
  for(i=0;i<2;i++){
    for(j=0;j<2;j++){
      printf("%d ", ans[i][j]);
    }
    printf("\n");
  }
  return 0;
}

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