First Issue:
arr[i].song = (char*)malloc(sizeof(char));
arr[i].artist = (char*)malloc(sizeof(char));
Are only allocating 1 byte for your char* pointers, song and artist. You can allocate a size for this:
arr[i].song = (char*)malloc(100 * sizeof(char)); /* or malloc(100) */
arr[i].artist = (char*)malloc(100 * sizeof(char));
Or you can simply malloc() enough space from you buffer:
char buffer[100];
fgets(buffer, 100, input);
/* check for failure, remove newline */
arr[i].song = malloc(strlen(buffer)+1);
/* check error from malloc */
strcpy(arr[i].song, buffer);
Or even use strdup():
arr[i].song = strdup(buffer);
Which is a substitute for malloc()/strcpy().
Note: You can also read Do I cast the result of malloc?.
Second Issue:
Your current struct:
typedef struct Song {
char *song;
char *artist;
int *year;
} Song;
Can be simplified to:
typedef struct {
char *song;
char *artist;
int year;
} Song;
Because year does not need to be a pointer. Easier to manage if its just an int. This avoids having to do allocations like:
arr[i].year = (int*)malloc(sizeof(int));
Other Recommendations:
You should check the return of fscanf() and fgets() as its safe to do this. It helps just incase your file will have incorrect data. This goes the same for malloc(), which can return NULL is unsuccessfully allocated on the heap.
Here is some code with the above considerations in mind:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define SIZE 100
typedef struct {
char *song;
char *artist;
int year;
} Song;
Song *create_array(FILE *input, int *nrof);
void load_data(Song *arr, FILE *input, int nrof);
void print_free_data(Song *arr, int nrof);
void get_buffer(char buffer[], FILE *input);
int main(void) {
FILE *input;
Song *arr;
int nrof;
input = fopen("artist.txt", "r");
if (input == NULL) {
fprintf(stderr, "Error reading file\n");
exit(EXIT_FAILURE);
}
arr = create_array(input, &nrof);
load_data(arr, input, nrof);
print_free_data(arr, nrof);
fclose(input);
return 0;
}
Song *create_array(FILE *input, int *nrof) {
Song *arr;
if (fscanf(input, "%d ", nrof) != 1) {
fprintf(stderr, "Cannot find number of songs\n");
exit(EXIT_FAILURE);
}
arr = malloc(*nrof * sizeof(*arr));
if (arr == NULL) {
fprintf(stderr, "Cannot allocate %d spaces for array\n", *nrof);
exit(EXIT_FAILURE);
}
return arr;
}
void load_data(Song *arr, FILE *input, int nrof) {
char buffer[SIZE];
for (int i = 0; i < nrof; i++) {
get_buffer(buffer, input);
arr[i].song = malloc(strlen(buffer)+1);
if (arr[i].song == NULL) {
fprintf(stderr, "Cannot allocate song\n");
exit(EXIT_FAILURE);
}
strcpy(arr[i].song, buffer);
get_buffer(buffer, input);
arr[i].artist = malloc(strlen(buffer)+1);
if (arr[i].artist == NULL) {
fprintf(stderr, "Cannot allocate artist\n");
exit(EXIT_FAILURE);
}
strcpy(arr[i].artist, buffer);
if (fscanf(input, "%d ", &arr[i].year) != 1) {
fprintf(stderr, "Cannot find year for Song: %s Album: %s\n",
arr[i].song, arr[i].artist);
exit(EXIT_FAILURE);
}
}
}
void get_buffer(char buffer[], FILE *input) {
size_t slen;
if (fgets(buffer, SIZE, input) == NULL) {
fprintf(stderr, "Error from fgets(), line not read\n");
exit(EXIT_FAILURE);
}
slen = strlen(buffer);
if (slen > 0 && buffer[slen-1] == '\n') {
buffer[slen-1] = '\0';
} else {
fprintf(stderr, "Too many characters entered\n");
exit(EXIT_FAILURE);
}
}
void print_free_data(Song *arr, int nrof) {
for (int i = 0; i < nrof; i++) {
printf("%s\n%s\n%d\n\n", arr[i].song, arr[i].artist, arr[i].year);
free(arr[i].song);
arr[i].song = NULL;
free(arr[i].artist);
arr[i].artist = NULL;
}
free(arr);
arr = NULL;
}
Which Outputs correct data:
Mr Tambourine Man
Bob Dylan
1965
Dead Ringer for Love
Meat Loaf
1981
Euphoria
Loreen
2012
Love Me Now
John Legend
2016
