One of my university assignments asked us to create a program using struct in order to create a simple event scheduler. This program is for a single day only, not multiple days.
Sample Input / Output
For a few reasons, I've opted to create a .GIF to display the sample input / output:
An example save file:
8 30 dentist_appointment 14 0 pickup_friend_from_airport 17 0 buisness_meeting_at_the_office 20 30 dinner_reservation
Disclaimer / Notice: The following code is not to be copied without proper credit. It is licensed under cc by-sa 3.0 with attribution required.
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <stdlib.h>
#include <ctype.h>
#define _MAX_EVENTS 10 // 10 Events Max
#define _MAX_DESCRIPTION 101 // 100 Character Description Max
typedef struct { // typedef a struct called event
int hour; // Store the hour / HH
int minute; // Store the minute / MM
char description[_MAX_DESCRIPTION]; // Store the event description
} event;
// Print the menu selection
void printMenu() {
puts("+------ SCHEDULER ------+\n"
"| 1. New Event |\n"
"| 2. Delete Event |\n"
"| 3. Display Schedule |\n"
"| 4. Save Schedule |\n"
"| 5. Load Schedule |\n"
"| 6. Exit |\n"
"+-----------------------+\n");
}
// Return true if an event is NULL, false otherwise
bool isNull(const event *e) { return e == NULL; }
// Allocate memory for and initialize an event
event *initEvent() {
event *e = (event*)malloc(sizeof(event));
e->hour = 0;
e->minute = 0;
strcpy(e->description, "");
return e;
}
// Take user input until value is between min and max inclusive, return the input
int inputRange(const int min, const int max) {
int input = 0;
char temp[21];
char *prompt = "| Enter a number between %d and %d: ";
printf(prompt, min, max);
fgets(temp, 21, stdin);
input = atoi(temp);
while (input > max || input < min) { // Data validation
printf(prompt, min, max);
fgets(temp, 21, stdin);
input = atoi(temp);
}
return input;
}
// Setup a new event with user input and return a pointer to the same event
event* newEvent(event *e) {
if (isNull(e)) { // If e is NULL
e = initEvent(); // Initialize it
}
char *seperator = "+--------------------------------+";
printf("\n%s\n| NEW EVENT |\n%s\n\n", seperator, seperator);
puts("+---------- EVENT TIME ----------+");
e->hour = inputRange(0, 23);
e->minute = inputRange(0, 59);
puts(seperator);
puts("\n+--- EVENT DESCRIPTION ---+");
printf("%s", "| Enter a description: ");
fgets(e->description, _MAX_DESCRIPTION, stdin);
puts("+-------------------------+\n");
puts("| Event successfully added.\n");
return e;
}
// Add an event to an event list at a specified index
void addEventAtIndex(event list[], const event e, const int i) {
if (isNull(&e)) { // if our event is NULL, return
return;
}
list[i].hour = e.hour;
list[i].minute = e.minute;
strcpy(list[i].description, e.description);
}
// Insertion sort by swapping struct members
void sort(event list[], const int size) {
for (int i = 1; i < size; i++) {
for (int j = i; j > 0 && (list[j - 1].hour > list[j].hour || (list[j - 1].hour == list[j].hour && list[j - 1].minute > list[j].minute)); j--) {
int hourJ = list[j].hour;
int minuteJ = list[j].minute;
char descriptionJ[_MAX_DESCRIPTION];
strcpy(descriptionJ, list[j].description);
int hourJMinus1 = list[j - 1].hour;
int minuteJMinus1 = list[j - 1].minute;
char descriptionJMinus1[_MAX_DESCRIPTION];
strcpy(descriptionJMinus1, list[j - 1].description);
list[j].hour = hourJMinus1;
list[j].minute = minuteJMinus1;
strcpy(list[j].description, descriptionJMinus1);
list[j - 1].hour = hourJ;
list[j - 1].minute = minuteJ;
strcpy(list[j - 1].description, descriptionJ);
}
}
}
// Add an event to an event list by sorting it into position
void sortInsert(event list[], int *size, event e) {
addEventAtIndex(list, e, *size); // Add event to the end of the list
(*size)++; // Increment size
// Insertion Sort
sort(list, *size);
}
// Display an event in a readable format: [ID] HH:MM - DESCRIPTION
void printEvent(const event e) {
char h1 = { (e.hour / 10) + '0' }; // Extract the first digit and convert to char (if any, else 0)
char h2 = { (e.hour - (e.hour / 10) * 10) + '0' }; // Extract the second digit and convert to char
char m1 = { (e.minute / 10) + '0' };
char m2 = { (e.minute - (e.minute / 10) * 10) + '0' };
printf("%c%c:%c%c - %s", h1, h2, m1, m2, e.description);
}
// Display all events in an event list
void printEventList(const event list[], const int size) {
if (size == 0) {
puts("\n| You have no events scheduled!\n");
return;
}
char *seperator = "+--------------------------------+";
printf("\n%s\n| MY SCHEDULE |\n%s\n\n", seperator, seperator);
for (int i = 0; i < size; i++) {
printf("| [%d] ", i);
printEvent(list[i]);
}
putchar('\n');
}
// Delete an event from an event list
void deleteEvent(event list[], int *size) {
if (*size == 0) { // If list is empty
puts("\n| Event list already empty.\n");
return;
}
char temp[21];
int id;
char *seperator = "\n+--------------------------------+";
printf("%s\n| DELETE EVENT |%s\n\n", seperator, seperator);
for (int i = 0; i < *size; i++) { // Display the event list so the user can see which event to delete
printf("| [%d] ", i);
printEvent(list[i]);
}
printf("%s", "\n| Enter the ID of an event to delete: ");
fgets(temp, 21, stdin);
id = atoi(temp);
if (id > *size - 1) {
printf("\n| No event located at %d\n", id);
return;
}
printf("| Event [%d] deleted successfully.\n\n", id);
// Set hour and minute to some trivially large value for sorting purposes
list[id].hour = 99;
list[id].minute = 99;
strcpy(list[id].description, "");
if (id != (*size - 1)) { // If the event to remove is already last, there's no need to sort it to last
sort(list, *size);
}
(*size)--; // Decrement the size of the list
}
// Replace all spaces in a string with an underscore
char *encode(char *s) {
for (int i = 0; i < strlen(s); i++) {
if (s[i] == ' ') {
s[i] = '_';
}
}
return s;
}
// Replace all underscores in a string with an spaces
char *decode(char *s) {
for (int i = 0; i < strlen(s); i++) {
if (s[i] == '_') {
s[i] = ' ';
}
}
return s;
}
// Save an event list to file
void saveEventList(char *filename, event list[], int size) {
FILE *f = fopen(filename, "w");
if (f == NULL) { // If our file is NULL, return
return;
}
for (int i = 0; i < size; i++) {
fprintf(f, "%d %d %s", list[i].hour, list[i].minute, encode(list[i].description)); // Encode the description (replace spaces with underscores) before saving it into the file
}
printf("\n| %d %s successfully saved into \"%s\".\n\n", size, (size == 1) ? "event" : "events", filename); // Tenary expression to make sure we're grammatically correct
fclose(f);
}
// Load an event list from file
void loadEventList(char *filename, event list[], int *size) {
FILE *f = fopen(filename, "r");
char temp[6 + _MAX_DESCRIPTION]; // ## ## MAX_DESCRIPTION_LENGTH
if (f == NULL) {
printf("\n| File \"%s\" not found.\n\n", filename);
return;
}
*size = 0; // Set size to 0
while (fgets(temp, sizeof(temp), f)) {
char *word = strtok(temp, " "); // Use space as the token delimiter, get the first token (hour)
list[*size].hour = atoi(word); // Store the token into the list
word = strtok(NULL, " "); // Get the second token (minute)
list[*size].minute = atoi(word);
word = strtok(NULL, " "); // Get the third token (description)
strcpy(list[*size].description, decode(word)); // Decode our word before copying it (remove underscores)
(*size)++; // Increment size with each line (event) added
}
printf("\n| %d %s successfully loaded from \"%s\".\n", *size, (*size == 1) ? "event" : "events", filename);
printEventList(list, *size); // Display the event list when finished, show the user what's been loaded
}
int main() {
event list[_MAX_EVENTS];
int index = 0; // Number of elements in list
int selection = 0;
char file[FILENAME_MAX];
char response = 'Y';
char temp[21];
while (selection != 6) {
printMenu(); // Print the menu
printf("%s", "| Please select an option: "); // Prompt for input
fgets(temp, 21, stdin);
selection = atoi(temp); // Convert string input to int
switch (selection) {
case 1: // New Event
if (index + 1 > _MAX_EVENTS) {
printf("| You can only have %d active events at one time!\n\n", index);
break;
}
sortInsert(list, &index, *newEvent(&list[index]));
break;
case 2: // Delete Event
deleteEvent(list, &index);
break;
case 3: // Display Schedule
printEventList(list, index);
break;
case 4: // Save Schedule
if (index == 0) { // No events, don't save anything
puts("| You have no events in your schedule!\n");
}
else {
printf("%s", "| Please enter a \"filename.txt\": ");
fgets(file, FILENAME_MAX, stdin);
strtok(file, "\n"); // Strip newline from filename
saveEventList(file, list, index);
}
break;
case 5: // Load Schedule
if (index > 0) {
printf("%s", "| Are you sure you want to discard your current schedule? (Y/N): ");
response = toupper(getc(stdin));
char c;
while (((c = getchar()) != '\n') && (c != EOF)); // Clear buffer, from getc();
}
if (response == 'Y') {
printf("%s", "| Please enter a \"filename.txt\": ");
fgets(file, FILENAME_MAX, stdin);
strtok(file, "\n"); // Strip newline from filename
loadEventList(file, list, &index);
}
break;
case 6: // Exit Program
puts("\n| Thank you!\n");
break;
default: // Error
puts("\n| Error in selection\n");
break;
}
}
}
Questions / Concerns
Hopefully I've improved since my last major code review. I've tried to keep the comments useful, so tell me if I'm still being redundant or need to tone that down. There's a few things I have kept in mind while writing this, including not repeating myself as best as possible.
Was the ASCII formatting when printing a good idea? Or should that just be left when showing the menu? In what ways can I improve, what shouldn't I be doing, and what should I be doing?