Getting wrong output from reading lines in a file in c program - c

Question

I need to get this output:
P1 0 3
P2 1 6
P3 4 4
P4 6 2
But instead I am getting this:
0 0 0
0 0 0
0 0 0
0 0 0
I am new to C programming. So, I don't know why I am getting wrong output. This is what I did. I am supposed to store each column in different variable. Because After storing them in different variable I need to do maths calculation for them.
#include<stdio.h>
#include<stdlib.h>
#include <string.h>
#include <math.h>
#include <stdint.h>
#include <stdbool.h>
int main (int argc, char *argv[]) {
FILE *fptr;
fptr = fopen(argv[1], "r");
if (fptr != NULL) {
size_t i;
int SIZE = 1000;
int*x[500];
int*y[500];
int*z[500];
int ch=0;
int l;
int n=0;
char line[100];
while ((ch=fgetc (fptr))!= EOF) {
if (ch=='\n')
n++;
}
printf("Number of lines = %d\n", n);
for (l=0; l<n;++l) {
while(fgets(line,sizeof line,fptr)) {
printf("%s",line);
sscanf(line,"%d %d %d",&x[l],&y[l],&z[l]);
}
}
for (i=0; i<l;++i) {
printf("%d %d %d\n",x[i],y[i],z[i]);
}
fclose(fptr);
return 0 ;
}

Answer 1

I see at least 2 issues.
The fptr has gone to the end of file while counting number of lines. So rewind() the fptr after counting lines, as it has gone up to the end of file. So add rewind(fptr) after first while loop.
You do not need x, y, z as array of pointers, rather just an array. So change them to
int x[500];
int y[500];
int z[500];

Answer 2

Okay, lets sort this out with comments first:
#include<stdio.h>
// i dont think the following includes are nessesary for the given code
//#include<stdlib.h>
//#include <string.h>
//#include <math.h>
//#include <stdint.h>
//#include <stdbool.h>
int main (int argc, char *argv[]) {
FILE *fptr;
// i wonder a little about what youre opening here with argv[1]
// since arrays start counting at 0
// for testing and more understandability maybe just put the file
// where your code is and deliver its filename as a string?
fptr = fopen(argv[1], "r");
if (fptr != NULL) {
// whats that? you use it as a counting variable, make it int
// not size_t
size_t i;
// its not good practive to have a variable in capitals
// if you wanna make it a constant, you should define it
// at the beginning of the code, right after your includes
int SIZE = 1000;
// dont use pointers (these -> "*") here! Maybe you mix up
// dynamic array declaration (which requires using malloc() and
// no brackets like "int * dynArray;") with static arrays
// correct usage would be: int x[500]; thats it
int*x[500];
int*y[500];
int*z[500];
int ch=0;
// just a hint for more readability: use "j" instead of "l" but
// thats really up to you :D
int l;
int n=0;
char line[100];
// here you loop through your file char by char and just count
// the lines. Why dont pick the chars on the fly and actually
// write something into your defined arrays x, y, z ?
// some additional conditions (if) may do the trick
while ((ch=fgetc (fptr))!= EOF) {
if (ch=='\n')
n++;
}
printf("Number of lines = %d\n", n);
// sizeof is a function, so youre missing the parentheses
// and above that, you already know the size of your line array
// because its statically defined to hold 100 * sizeof(char)
// my suggestion: trash this entire loop and rethink the previous
for (l=0; l<n;++l) {
while(fgets(line,sizeof line,fptr)) {
printf("%s",line);
sscanf(line,"%d %d %d",&x[l],&y[l],&z[l]);
}
}
// cool loop. but there was no input to x, y, z except the first
// element of your line array, which seems to hold just a 0
// so everythings correct here, the mistake occured before
for (i=0; i<l;++i) {
printf("%d %d %d\n",x[i],y[i],z[i]);
}
//nice, thats important :)
fclose(fptr);
return 0 ;
}
i hope it helps you sort out things and may guide to a clearer question which maybe answeres itself? :D