Segmentation fault error when I try to run this program

Question

#include <stdio.h>
#include <stdlib.h>
#include "vettore.h"

int main(int argc, char *argv[]){
    if(argc != 5)
        printf("Incorrect parameters number\n");
    else{
        int n = atoi(argv[1]);
        int *a = (int*) calloc(n, sizeof(int));
        if(a == NULL)
            printf("Unsufficient memory\n");
        else{
            finput_array(argv[2], a, n);
            bubblesort(a, n);
            foutput_array(argv[4], a, n);
            int *oracle = (int*) calloc(n, sizeof(int));
            finput_array(argv[3], oracle, n);

            if(compare_array(a, oracle, n))
                printf("PASS\n");
            else
                printf("FAIL\n");
        }
    }
}

I run the program this way: ./test_ordina_array.exe 12 TC4_input.txt TC4_oracle.txt TC4_output.txt but it gives me segmentation fault.

"TC4_output.txt" is created by the program while the other two files already exist.

This are the functions used:

    void bubblesort(int a[], int n){
int i, j;
  for(i = 0 ; i < n - 1; i++)
  {
    for(j = 0 ; j < n - i - 1; j++)
    {
      if (a[j] > a[j+1]) /* For decreasing order use < */
      {
        swap(&a[j], &a[j+1]);
       }
      }
     }
}

void finput_array(char *file_name, int a[], int *n){
    FILE *fd = fopen(file_name, "r");
    if(fd == NULL)
        printf("Errore in apertura del file %s\n", file_name);
    else{
        int i = 0;
        fscanf(fd, "%d", &a[i]);
        while(i<*n && !feof(fd)){
            i++;
            fscanf(fd, "%d", &a[i]);
        }
        fclose(fd);
        if(i<*n)
            *n = i;
    }
}

void foutput_array(char *file_name, int a[], int n){
    int i;
    FILE *fd;

    fd = fopen(file_name, "w");
    if(fd == NULL)
        printf("Errore in apertura del file %s\n", file_name);
    else{
        for(i=0; i<n; i++)  
            fprintf(fd, "%d\n", a[i]);
        fclose(fd);
    }
}

int compare_array(int a[], int b[], int n){
    int i=0;

    while(i<n && a[i] == b[i])
        i++;

    return (i==n) ? 1 : 0;
}

They are contained in "vettore.c" and "vettore.h" contains their prototypes.

The program has to order in ascending order the elements contained in the first txt file and write them in the output file.

The crash probably happens in the parts of the code you *don't* show us. Please use a debugger to catch the crash and locate when and where in your code it happens. — Some programmer dude, Feb 19 '19 at 14:14
Have you declared the function properly? Because there's a mismatch between the shown declaration of `finput_array` and how you call it. — Some programmer dude, Feb 19 '19 at 14:22
Also please read [Why is “while (!feof(file))” always wrong?](https://stackoverflow.com/questions/5431941/why-is-while-feoffile-always-wrong) — Some programmer dude, Feb 19 '19 at 14:23
we need all the (non C-standard) dependancies.... also little sample input and desired output for that input would be a nice to have — DDS, Feb 19 '19 at 14:25
Didn't you get any compiler warnings or did you just ignore them? 1) Turn your compilers warning level to maximum. 2) Always take warnings seriously, i.e. fix them — Support Ukraine, Feb 19 '19 at 14:42
Didn't you get a warning in this line: `finput_array(argv[2], a, n);`? — Jabberwocky, Feb 19 '19 at 14:50

score 3 · Accepted Answer · answered Feb 19 '19 at 14:26

3

You have problem when using finput_array

finput_array(argv[2], a, n);

Please replace by

finput_array(argv[2], a, &n);

answered Feb 19 '19 at 14:26

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Segmentation fault error when I try to run this program

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