You are tasked with developing a student data management system in C that allows users to save, display, and update student records. Each record includes the student's registration number, name, branch, and admission year. The program should enable users to:
Save Data: Capture student information from user input and save it in a binary file (stdata.vgt) in append mode, storing each record in a structured format.
Display Data: Read all saved records from the file and display them in a formatted table view, showing fields like registration number, name, branch, and admission year.
Update Data: Prompt the user to enter a specific record number, retrieve the corresponding student record, and allow updates to the information. After confirmation, the updated record should overwrite the previous one at the correct file position.
Exit Program: Terminate the program when the user chooses.
The program should handle various scenarios, such as file access errors, record number validation, and confirmatory messages for successful updates, with proper prompts and messages to guide the user through each option.