File Handling in C Interview Questions and Answers (Top 50 Questions for Freshers and Experienced)

• Permanent data storage
• Data sharing between programs
• Efficient handling of large datasets
• Data backup and recovery

FILE *fp;

FILE *fp;

fp = fopen("data.txt","r");

if(fp == NULL)
{
    printf("File cannot be opened");
}

• r → Read only
• r+ → Read and write

• w overwrites existing content.
• a adds data at the end of the file.

fclose(fp);

• Data loss
• Memory leaks
• File corruption
• Resource wastage

• scanf() reads from keyboard.
• fscanf() reads from file.

char ch;
ch = fgetc(fp);

• fgetc() reads one character.
• fgets() reads an entire line.

fprintf(fp,"%d",num);

• fputc() writes one character.
• fputs() writes a string.

feof(fp);

fseek(fp,10,SEEK_SET);

• SEEK_SET → Beginning
• SEEK_CUR → Current position
• SEEK_END → End of file

FILE *fp = fopen("data.txt","r");

if(fp != NULL)
{
   printf("Exists");
}

• Sequential access reads data in order.
• Random access jumps directly to any location.

• Permanent storage
• Large data capacity
• Data sharing
• Data backup

#include <stdio.h>

fopen("file.txt","w");

fopen("filename","mode");

remove("file.txt");

rename("old.txt","new.txt");

• fread() reads binary data.
• fscanf() reads formatted text data.

• fwrite() writes binary data.
• fprintf() writes formatted text.

• fopen()
• fclose()
• fscanf()
• fprintf()
• fgetc()
• fputc()
• fgets()
• fputs()
• fread()
• fwrite()
• fseek()
• ftell()
• rewind()
• feof()