Reading two matrices from one txt file - c

Question

I'm having trouble with one task.
I need to read two matrices from a text file and multiply them together.
The problem is that I know how to read one matrix but I don't understand how to read the two matrices separated (for example) by two spaces in a file.
Matrix.txt:
1 2 3 1 2 3
4 5 6 4 5 6
7 8 9 7 8 9
Maybe someone could explain me how to do that.
Now i'm trying to read first matrix:
#include <stdlib.h>
#include <stdio.h>
int main(){
FILE *fp;
int eSk = 0, sSk = 0,
matrix1[10][10] = {0}, i, j;
char c;
fp = fopen("matrix.txt", "r+");
while(!feof(fp)) {
while(getc(fp) != ' ') {
fscanf(fp, "%d", &matrix1[eSk][sSk]);
sSk++;
}
eSk++;
}
for(i = 0; i < eSk; i++) {
for(j = 0; j < sSk; j++) {
printf("%d ", matrix1[eSk][sSk]);
}
printf("\n");
}
puts("");
system("pause");
return 0;
}
what's wrong ?
Thank you for any help.

Answer 1

You need to skip the second matrix while reading the first and viceversa. Try this:
#include <stdio.h>
#include <stdlib.h>
int main(void) {
FILE *file;
int matrixA[3][3], matrixB[3][3];
int garbage[3];
int i, j, k;
i = j = k = 0;
file = fopen("matrix.txt", "rt");
/* Read the first matrix */
for (i = 0; i < 3; i++) {
for (j = 0; j < 3; j++) {
fscanf(file, "%d", &matrixA[i][j]);
}
/* Skip the second matrix */
for (k = 0; k < 3; k++) fscanf(file, "%d", &garbage[k]);
}
/* Reposition the stream */
fseek(file, 0, SEEK_SET);
/* Read the second matrix */
for (i = 0; i < 3; i++) {
/* Skip the first matrix */
for (k = 0; k < 3; k++) fscanf(file, "%d", &garbage[k]);
for (j = 0; j < 3; j++) {
fscanf(file, "%d", &matrixB[i][j]);
}
}
/* Multiply them ... */
/* Show first matrix */
for (i = 0; i < 3; i++) {
printf("\n");
for (j = 0; j < 3; j++) {
printf(" %d ", matrixA[i][j]);
}
}
printf("\n");
/* Show second matrix */
for (i = 0; i < 3; i++) {
printf("\n");
for (j = 0; j < 3; j++) {
printf(" %d ", matrixB[i][j]);
}
}
return 0;
}

Answer 2

If the format of the string is standardized, you can read both matrices at one go. For your example above, please find a modified version as below.
int main(){
FILE *fp;
int eSk = 0, sSk = 0, i, j;
int mat1[3][3], mat2[3][3];
char line[256];
char c;
fp = fopen("matrix.txt", "r+");
if(NULL == fp) {
printf("Can't open the file\n");
exit(-1);
}
// Read one line
fgets(line, 256, fp);
while(!feof(fp)) {
// Convert line to array
sscanf(line,"%d %d %d %d %d %d", &mat1[eSk][0], &mat1[eSk][1], &mat1[eSk][2], &mat2[eSk][0], &mat2[eSk][1], &mat2[eSk][2]);
// Increment counter
eSk++;
//Read next line
fgets(line, 256, fp);
}
printf("Matrix1\n");
for(i = 0; i < eSk; i++) {
for(j = 0; j < 3; j++) {
printf("%d ", mat1[i][j]);
}
printf("\n");
}
printf("Matrix2\n");
for(i = 0; i < eSk; i++) {
for(j = 0; j < 3; j++) {
printf("%d ", mat2[i][j]);
}
printf("\n");
}
puts("");
system("pause");
return 0;
}