ignoring # when reading from text file [closed] - c

Question

Closed. This question needs details or clarity. It is not currently accepting answers.
Want to improve this question? Add details and clarify the problem by editing this post.
Closed 7 years ago.
Improve this question
I have the following text file
#1234
5,4
#tfxc
01AAX
11AA1
#tfxc
11AA1
11111
And I want to ignore the # and the data behind it when reading from the text file and the 5,4 are the dimensions of the matrix which I am storing in a 2d array.
This is my code:
#include <stdio.h>
FILE *inp;
int main(void) {
int i, j;
int y = 0;
int x = 0;
char comma;
char arr = 0;
inp = fopen("App.txt", "r");
fscanf(inp, "%d", &x);
fscanf(inp, "%c", &comma);
fscanf(inp, "%d", &y);
char array[y][x];
for (i = 0; i < y; i++) {
for (j = 0; j < x; j++) {
fscanf(inp, "%c", &arr);
if ((arr == '1') || (arr == 'X') || (arr == '0') || (arr == 'A')) {
array[i][j] = arr;
} else {
j--;
}
printf("%c", arr);
}
}
}
How I can do this?

Answer 1

Use fgets() to read lines, check if the line should be ignored, else parse the line to initialize your matrix.
Here is an example:
#include <stdio.h>
int main(void) {
int c, i, j, k, x = 0, y = 0;
char line[1024];
FILE *inp;
inp = fopen("App.txt", "r");
if (inp == NULL) {
printf("cannot open App.txt\n");
exit(1);
}
while (fgets(line, sizeof line, fp)) {
if (line[0] == '#') continue;
if (sscanf(line, "%d,%d", &x, &y) == 2)
break;
printf("invalid line: %s", line);
exit(1);
}
char array[y][x];
for (i = 0; i < y;) {
if (!fgets(line, sizeof line, inp)) {
printf("missing matrix data at row %d\n", i);
break;
}
if (line[0] == '#')
continue;
for (j = k = 0; j < x && line[k] != '\0'; k++) {
c = line[k];
if (c == '1' || c == 'X' || c == '0' || c == 'A') {
array[i][j] = c;
j++;
putchar(c);
}
}
putchar('\n');
if (j != x) {
printf("missing matrix values at %d,%d\n", i, j);
}
i++;
}
fclose(inp);
return 0;
}

Answer 2

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void) {
int i, j;
int y = 0, x = 0;
FILE *inp = fopen("App.txt", "r");
if(!inp){
perror("fopen\n");
exit(EXIT_FAILURE);
}
while(2 != fscanf(inp, "%d,%d", &x, &y)){
int ch;
while((ch=fgetc(inp)) != '\n' && ch !=EOF);//skip
if(ch == EOF){
fprintf(stderr, "There is no dimension specified.\n");
exit(EXIT_FAILURE);
}
}
char array[y][x];
char format[32];
sprintf(format, "%%%d[01AX]%%c", x);
for (i = 0; i < y; i++) {
int status;
char newline = 0, buff[x+1];
status = fscanf(inp, format, buff, &newline);
if(status == 0 || status == 2 && newline != '\n'){//status 1 is OK
int ch;
while((ch=fgetc(inp)) != '\n' && ch !=EOF);//skip
--i;
continue;
}
if(status == EOF){
fprintf(stderr, "Necessary data is missing.\n");
exit(EXIT_FAILURE);
}
memcpy(array[i], buff, x);
}
fclose(inp);
//check print
for (i = 0; i < y; i++) {
for (j = 0; j < x; j++) {
putchar(array[i][j]);
}
putchar('\n');
}
return 0;
}