[ECP 1016]Tutorial 11 Question 3 [LecturerTANG SZE YIN]

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// Solution for Question 3 Tutorial 11
#include <stdio.h>
#include <stdlib.h>
// Part (a) Define a structure called Participant.
struct Participant
{
    int id;
char name[20];
    int time;
};
// Function prototype for find.
void find(struct Participant * list, int size, struct Participant * win);
int main()
{
    // (b) Deduce the total number of participants from the file “results.txt”.
FILE * fptr;      // file pointer
    int count = 0;    // to count total number of participants
    char buff[100];   // temporary buffer for fgets
    fptr = fopen("results.txt", "r");
    if (fptr == NULL)
    {
        printf("Error opening file to read.\n");
        return 1;
    }
while (!feof(fptr))
    {
        fgets(buff, 100, fptr);
        count++;
    }
printf("Total number of participants: %d\n", count);

// (c) Declare a pointer of type struct Participant named listptr.
// Use dynamic memory allocation to allocate memory space.
struct Participant * listptr;    // pointer to a list of participant records
    listptr = (struct Participant *) calloc(count, sizeof(struct Participant));

// (d) Design a for loop to read information from the file “results.txt”
// to the memory space pointed by listptr.
int i;
rewind(fptr);    // rewind the pointer to the beginning
    for (i=0; i<count; i++)
    {
        fscanf(fptr, "%d %s %d", &listptr[i].id, listptr[i].name, &listptr[i].time);
    }
fclose(fptr);    // close the file

// (f) Write the winner information to the end of the file “results.txt”.
struct Participant winner;          // the winner record
    find(listptr, count, &winner);       // call function find
    fptr = fopen("results.txt", "a+");   // append if file exists
    if (fptr == NULL)
    {
        printf("Error opening file to append.\n");
        return 1;
    }
fprintf(fptr, "\n\nThe winner is %s (ID: %d), time taken %ds.",
                  winner.name, winner.id, winner.time);
    fclose(fptr);