/* 
Program: matrix-product-file-v0.c (Report comments/bugs to chikh@yuntech.edu.tw)
Function: 讀取檔案設定矩陣元素，設置好A與B矩陣之後，實作矩陣相乘
Note: 預設讀取matrixData1.txt；matrixData2.txt用於測試A與B維度不符的狀況 
*/

#include <stdio.h>

#define N 100 

int rowA, colA, rowB, colB;	
char idA, idB;

int init(int A[][N], int B[][N])	//初始化A與B矩陣 
{
	FILE *f; 
	int  i, j;
	
	f = fopen("matrixData1.txt","r");
	//f = fopen("matrixData2.txt","r");
	fscanf(f,"%c %d %d %c %d %d",&idA,&rowA,&colA,&idB,&rowB,&colB);
	if (colA != rowB) return 0;	
	for (i = 0; i < rowA; i++)
		for (j = 0; j < colA; j++)
			fscanf(f,"%d",&A[i][j]);
	for (i = 0; i < rowB; i++)
		for (j = 0; j < colB; j++)
			fscanf(f,"%d",&B[i][j]);
	
	return 1;
}

void mul(int A[][N], int B[][N], int C[][N])	//實作C=A*B矩陣相乘運算，運算結果存入C 
{
	int i, j, k, sum;
	
	for (i = 0; i < rowA; i++) {   
		for (j = 0; j < colB; j++) {
			for (sum = k = 0; k < colA; k++)
				sum += A[i][k]*B[k][j];
			C[i][j] = sum;
		}
	} 
}

void show(char p, char q, int X[][N], int row, int col) 
{
	int i, j;
	
	if (q != '-') //以q來區隔顯示模式的差異 
		printf("\nMatrix %c*%c =\n",p,q);
	else
		printf("\nMatrix %c =\n",p);
	
	for (i = 0; i < row; i++) {   
		for (j = 0; j < col; j++) printf("%6d",X[i][j]);
		printf("\n");
	}
	printf("\n");
}

int main() 
{
	int A[N][N] = {0}, B[N][N] = {0}, C[N][N] = {0}, D[N][N] = {0};	
	
	printf("\n*** 讀取描述矩陣的檔案，進行矩陣乘積運算 ***\n\n");
	if (init(A,B)==0) {
		printf("矩陣維度有誤，無法運算，sorry\n");
		return -1;
	}
	mul(A,B,C);
	show('A','-',A,rowA,colA);
	show('B','-',B,rowB,colB);
	show('A','B',C,rowA,colB);
	
  	return 0;
}