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

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