Free Time Slot Finder

Calender_merge is a C program that merges busy time intervals from one or more CSV files and outputs all available free time slots within a specified daily window. It supports filtering by minimum free slot duration. Basically it is a neat tool for coordinating with other students in a group project.

Input schedual format

The format is specified per .csv generated by TimeEdit (which my University uses).

Each line in the .csv must contain four fields:

• start_date: YYYY-MM-DD
• start_time: HH:MM
• end_date: YYYY-MM-DD
• end_time: HH:MM

Example

Data:

schedual1.csv:

2025-09-08,10:15,2025-09-08,12:00
2025-09-08,13:15,2025-09-08,15:00

schedual2.csv:

2025-09-08,08:15,2025-09-08,10:00
2025-09-08,13:15,2025-09-08,17:00

schedual3.csv:

2025-09-08,10:15,2025-09-08,12:00
2025-09-08,15:15,2025-09-08,17:00

Run:

./freeslots -w 08:15-17:00 -m 60 cal1.csv cal2.csv cal3.csv

Output:

Date         Start   End     Durmation(min)
2025-09-08   12:00   13:15   75

Build

gcc -o nob nob.c && ./nob main

Find all free slots in default window (00:00–24:00)

./freeslots cal1.csv

Only consider free slots longer than 30 minutes

./freeslots -m 30 cal1.csv

Limit search to working hours (08:15-17:00)

./freeslots -w 08:15-17:00 cal1.csv

Expand serach to find free slots that from multiple schedules

./freeslots -w 08:15-17:00 -m 60 cal1.csv cal2.csv cal3.csv

Clean

./nob clean