Having problems Qsort'ing struct *array based on 2 parameters
Question
Eow, I was working on a program which would take in a.txt with a list of football matches ie team, scores, date etc. and store these in a struct *array (match array). After this I run through the matches and assign points to the teams based on win/draw/loss and also the sum of their goals minus goals against them, these are stored in a struct *array (team array)
Now what i wanna do is sort this array based firstly on points, and if its even then based on the goals sum so the top rated teams is placed first, and the bottom placed team, last.
I'm new to Qsort, so i was wondering what i was messing up here. it seems my data gets completely corrupted.
Any help would be much appreciated
Update: commenter helped me figure out what was corrupting my data which has been fixed now, and also corrected a logic error in my compare_func for qsort, however my qsort still doesnt sort my array in any logical manner, it does however move my structs around. So I'm still looking for some assistance as to why it doesn't properly sort. Code has been updated to reflect changes
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
#define MSIZE 132
#define TSIZE 12
typedef struct match
{
char weekday[10], date[10], time[10], home[10], away[10], spectators[10];
int home_goal, away_goal;
} match;
typedef struct team
{
char teamname[4];
int point, goals, goals_against, goals_sum;
} team;
void fill_match_array(match *match_array[MSIZE]);
void allocate_space_team(team *team_array[TSIZE]);
void fill_team_array(team *team_array[TSIZE], match *match_array[MSIZE]);
int compare_function(const void *left, const void *right);
int main(void){
match *match_array[MSIZE];
team *team_array[TSIZE];
allocate_space_team(team_array);
fill_match_array(match_array);
for (int i = 0; i < MSIZE; i++)
{
printf("%s | %s | %s | %s | %s | - | %d | - | %d | %s\n", match_array[i]->weekday, match_array[i]->date, match_array[i]->time, match_array[i]->home, match_array[i]->away, match_array[i]->home_goal, match_array[i]->away_goal, match_array[i]->spectators);
}
printf("\n\n\n\n\n");
fill_team_array(team_array, match_array);
for (int i = 0; i < TSIZE; i++)
{
printf("%s | %d | %d | %d | %d\n", team_array[i]->teamname, team_array[i]->point, team_array[i]->goals, team_array[i]->goals_against, team_array[i]->goals_sum);
}
printf("\n\n\n\n\n");
qsort(team_array, TSIZE, sizeof(team*), compare_function);
for (int i = 0; i < TSIZE; i++)
{
printf("%s | %d | %d | %d | %d\n", team_array[i]->teamname, team_array[i]->point, team_array[i]->goals, team_array[i]->goals_against, team_array[i]->goals_sum);
}
return 0;
}
void fill_match_array(match *match_array[MSIZE]){
FILE *output_file_pointer;
output_file_pointer = fopen("kampe-2020-2021.txt", "r");
char x[5], y[5], home_goal[10], away_goal[10];
for (int i = 0; i < MSIZE; i++)
{
match_array[i] = malloc(sizeof(match));
fscanf(output_file_pointer, "%s %s %s %s %s %s %s %s %s %s", match_array[i]->weekday, match_array[i]->date, match_array[i]->time, match_array[i]->home, x, match_array[i]->away, home_goal, y, away_goal, match_array[i]->spectators);
match_array[i]->home_goal = atoi(home_goal);
match_array[i]->away_goal = atoi(away_goal);
//printf("%s | %s | %s | %s | %s | %s | %d | %s | %d | %s\n", match_array[i]->weekday, match_array[i]->date, match_array[i]->time, match_array[i]->home, x, match_array[i]->away, match_array[i]->home_goal, y, match_array[i]->away_goal, match_array[i]->spectators);
}
fclose(output_file_pointer);
}
void allocate_space_team(team *team_array[TSIZE]){
for (int i = 0; i < TSIZE; i++)
{
team_array[i] = malloc(sizeof(team));
team_array[i]->goals = 0;
team_array[i]->goals_against = 0;
team_array[i]->goals_sum = 0;
team_array[i]->point = 0;
}
strcpy(team_array[0]->teamname, "SDR");
strcpy(team_array[1]->teamname, "ACH");
strcpy(team_array[2]->teamname, "LBK");
strcpy(team_array[3]->teamname, "BIF");
strcpy(team_array[4]->teamname, "OB");
strcpy(team_array[5]->teamname, "AGF");
strcpy(team_array[6]->teamname, "FCM");
strcpy(team_array[7]->teamname, "FCK");
strcpy(team_array[8]->teamname, "RFC");
strcpy(team_array[9]->teamname, "VB");
strcpy(team_array[10]->teamname, "AaB");
strcpy(team_array[11]->teamname, "FCN");
}
void fill_team_array(team *team_array[TSIZE], match *match_array[MSIZE]){
for (int i = 0; i < TSIZE; i++)
{
for (int j = 0; j < MSIZE; j++)
{
if (strcmp(team_array[i]->teamname, match_array[j]->home) == 0)
{
team_array[i]->goals += match_array[j]->home_goal;
team_array[i]->goals_against += match_array[j]->away_goal;
if (match_array[j]->home_goal > match_array[j]->away_goal)
{
team_array[i]->point += 3;
}
else if (match_array[j]->home_goal == match_array[j]->away_goal)
{
team_array[i]->point += 1;
}
}
else if (strcmp(team_array[i]->teamname, match_array[j]->away) == 0)
{
team_array[i]->goals += match_array[j]->away_goal;
team_array[i]->goals_against += match_array[j]->home_goal;
if (match_array[j]->away_goal > match_array[j]->home_goal)
{
team_array[i]->point += 3;
}
else if (match_array[j]->home_goal == match_array[j]->away_goal)
{
team_array[i]->point += 1;
}
}
}
team_array[i]->goals_sum = team_array[i]->goals - team_array[i]->goals_against;
}
}
int compare_function(const void *left, const void *right){
const team *a = (const team *)left;
const team *b = (const team *)right;
if (a->point > b->point)
{
return -1;
}
else if (a->point < b->point)
{
return 1;
}
if (a->goals_sum > b->goals_sum)
{
return -1;
}
else if (a->goals_sum < b->goals_sum)
{
return 1;
}
else if (a->goals_sum == b->goals_sum)
{
return 0;
}
}
The txt.file to make it run -> should be named "kampe-2020-2021.txt"
Fre 11/09 19.00 SDR - FCM 2 - 0 2210
Son 13/09 14.00 ACH - RFC 0 - 3 1216
Son 13/09 14.00 LBK - AaB 0 - 0 2138
Son 13/09 16.00 BIF - FCN 3 - 2 6775
Son 13/09 18.00 OB - FCK 3 - 2 4315
Man 14/09 19.00 AGF - VB 4 - 2 7547
Lor 19/09 15.30 FCM - LBK 1 - 0 300
Son 20/09 14.00 FCK - BIF 1 - 2 277
Son 20/09 14.00 OB - FCN 1 - 1 300
Son 20/09 16.00 RFC - AGF 1 - 1 300
Son 20/09 18.00 VB - SDR 4 - 1 350
Man 21/09 19.00 AaB - ACH 1 - 0 280
Lor 26/09 17.00 FCM - RFC 1 - 0 300
Son 27/09 14.00 AGF - OB 4 - 2 300
Son 27/09 14.00 SDR - AaB 3 - 1 300
Son 27/09 16.00 BIF - ACH 2 - 1 300
Son 27/09 18.00 VB - FCK 2 - 2 350
Man 28/09 19.00 FCN - LBK 4 - 1 300
Fre 02/10 19.00 RFC - BIF 1 - 2 300
Son 04/10 14.00 LBK - SDR 2 - 2 300
Son 04/10 14.00 OB - VB 0 - 1 300
Son 04/10 16.00 AaB - AGF 1 - 1 280
Son 04/10 18.00 ACH - FCM 2 - 2 300
Son 04/10 20.00 FCK - FCN 3 - 2 220
Lor 17/10 16.00 FCM - OB 3 - 1 300
Son 18/10 14.00 AGF - ACH 3 - 0 300
Son 18/10 14.00 VB - LBK 3 - 2 350
Son 18/10 16.00 SDR - BIF 2 - 0 300
Son 18/10 18.00 FCK - AaB 1 - 2 242
Man 19/10 19.00 FCN - RFC 1 - 0 300
Fre 23/10 19.00 LBK - OB 0 - 3 300
Lor 24/10 18.00 BIF - FCM 2 - 3 300
Son 25/10 14.00 ACH - FCN 1 - 1 300
Son 25/10 16.00 RFC - SDR 1 - 2 300
Son 25/10 18.00 AGF - FCK 0 - 1 300
Man 26/10 19.00 AaB - VB 1 - 3 300
Fre 30/10 19.00 VB - RFC 0 - 3 350
Lor 31/10 16.00 FCN - FCM 4 - 1 300
Son 01/11 14.00 OB - ACH 1 - 0 300
Son 01/11 16.00 FCK - LBK 4 - 2 247
Son 01/11 18.00 AaB - BIF 2 - 1 300
Man 02/11 19.00 SDR - AGF 1 - 1 300
Fre 06/11 19.00 RFC - AaB 1 - 2 300
Son 08/11 14.00 FCN - VB 1 - 1 300
Son 08/11 14.00 LBK - AGF 1 - 2 300
Son 08/11 16.00 BIF - OB 3 - 1 300
Son 08/11 18.00 FCM - FCK 4 - 0 300
Son 08/11 20.00 ACH - SDR 0 - 3 300
Fre 20/11 19.00 LBK - ACH 1 - 1 300
Son 22/11 14.00 OB - SDR 1 - 1 300
Son 22/11 14.00 AaB - FCN 1 - 1 300
Son 22/11 16.00 AGF - FCM 1 - 2 300
Son 22/11 18.00 VB - BIF 0 - 2 350
Man 23/11 19.00 FCK - RFC 1 - 2 246
Fre 27/11 19.00 RFC - OB 2 - 1 300
Lor 28/11 16.00 FCM - AaB 0 - 0 300
Son 29/11 14.00 ACH - VB 3 - 1 300
Son 29/11 16.00 SDR - FCK 1 - 3 300
Son 29/11 18.00 FCN - AGF 3 - 1 300
Man 30/11 19.00 BIF - LBK 4 - 1 300
Fre 04/12 19.00 OB - AaB 2 - 1 300
Lor 05/12 16.00 VB - FCM 0 - 2 350
Son 06/12 14.00 SDR - FCN 2 - 1 300
Son 06/12 16.00 FCK - ACH 2 - 0 226
Son 06/12 18.00 LBK - RFC 0 - 3 300
Man 07/12 19.00 AGF - BIF 3 - 1 300
Fre 11/12 19.00 RFC - VB 3 - 1 300
Son 13/12 14.00 ACH - AGF 1 - 2 300
Son 13/12 14.00 AaB - LBK 3 - 2 300
Son 13/12 16.00 FCN - FCK 0 - 1 300
Son 13/12 18.00 BIF - SDR 2 - 1 300
Man 14/12 19.00 OB - FCM 1 - 1 300
Son 20/12 14.00 SDR - RFC 0 - 1 300
Son 20/12 14.00 LBK - VB 0 - 0 300
Son 20/12 16.00 AGF - AaB 3 - 0 300
Son 20/12 18.00 FCK - OB 1 - 1 242
Son 20/12 20.00 ACH - BIF 1 - 2 300
Man 21/12 19.00 FCM - FCN 3 - 1 300
Tir 02/02 18.00 RFC - ACH 3 - 0 0
Tir 02/02 20.00 VB - AGF 0 - 0 0
Ons 03/02 18.00 OB - LBK 0 - 1 0
Ons 03/02 20.00 AaB - FCK 2 - 3 0
Tor 04/02 18.00 FCM - SDR 1 - 2 0
Tor 04/02 20.00 FCN - BIF 0 - 1 0
Son 07/02 14.00 SDR - VB 0 - 1 0
Son 07/02 14.00 FCN - OB 0 - 2 0
Son 07/02 16.00 ACH - FCK 0 - 2 0
Son 07/02 18.00 AGF - LBK 1 - 0 0
Son 07/02 20.00 BIF - AaB 1 - 1 0
Man 08/02 19.00 RFC - FCM 1 - 2 0
Son 14/02 14.00 AaB - RFC 0 - 0 0
Son 14/02 14.00 VB - FCN 2 - 2 0
Son 14/02 16.00 LBK - BIF 0 - 4 0
Son 14/02 18.00 FCM - ACH 1 - 0 0
Son 14/02 20.00 OB - AGF 0 - 0 0
Man 15/02 19.00 FCK - SDR 3 - 2 0
Fre 19/02 19.00 AaB - FCM 0 - 2 0
Son 21/02 14.00 RFC - FCN 1 - 1 0
Son 21/02 14.00 ACH - OB 0 - 0 0
Son 21/02 16.00 AGF - SDR 2 - 0 0
Son 21/02 18.00 BIF - VB 2 - 1 0
Man 22/02 19.00 LBK - FCK 2 - 2 0
Fre 26/02 19.00 VB - ACH 0 - 0 0
Son 28/02 14.00 OB - RFC 2 - 1 0
Son 28/02 14.00 FCN - AaB 2 - 2 0
Son 28/02 16.00 FCK - AGF 3 - 3 0
Son 28/02 18.00 FCM - BIF 1 - 0 0
Man 01/03 19.00 SDR - LBK 1 - 4 0
Ons 03/03 18.00 AGF - FCN 0 - 1 0
Ons 03/03 18.00 ACH - AaB 2 - 1 0
Ons 03/03 20.00 FCK - VB 2 - 1 0
Tor 04/03 18.00 SDR - OB 1 - 1 0
Tor 04/03 18.00 LBK - FCM 2 - 0 0
Tor 04/03 20.00 BIF - RFC 0 - 0 0
Son 07/03 12.00 RFC - LBK 1 - 2 0
Son 07/03 14.00 BIF - FCK 2 - 1 0
Son 07/03 16.00 FCM - AGF 0 - 1 0
Son 07/03 18.00 FCN - ACH 2 - 2 0
Son 07/03 20.00 VB - OB 2 - 0 0
Man 08/03 19.00 AaB - SDR 1 - 0 0
Fre 12/03 19.00 LBK - FCN 0 - 3 0
Son 14/03 14.00 SDR - ACH 2 - 0 0
Son 14/03 14.00 VB - AaB 0 - 2 0
Son 14/03 16.00 OB - BIF 0 - 3 0
Son 14/03 18.00 FCK - FCM 0 - 0 0
Man 15/03 19.00 AGF - RFC 1 - 1 0
Son 21/03 17.00 BIF - AGF 1 - 1 0
Son 21/03 17.00 FCM - VB 5 - 0 0
Son 21/03 17.00 RFC - FCK 2 - 1 0
Son 21/03 17.00 ACH - LBK 1 - 2 0
Son 21/03 17.00 FCN - SDR 2 - 1 0
Son 21/03 17.00 AaB - OB 0 - 2 0
1 answers
solution1
1 2021-12-11 00:11:56
team_array is an array of pointers to a team. So a pointer to an element in that array will be a pointer to a pointer to a team.
int compare_function(const void *left, const void *right) {
const team *const *apnt = left;
const team *const *bpnt = right;
const team *a = *apnt;
const team *b = *bpnt;
Overall, in your code, I see no reason for using any arrays of pointers and even to dynamically allocate memory. If you know the size of memory you are going to allocate, there is no reason to use dynamic allocation. Remove all the pointers, change all the -> into . and just use normal arrays.
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