What is File Handling in C ?

Jab program chalu hota hai aur close ho jata hai, tab usme ki gayi calculations ya data memory se hat jaata hai. Par agar aap chaahte ho ki data permanently store ho, toh aapko files ka use karna padega.

What is File Handling?

File handling ka matlab hai data ko files ke through read/write karna. Isse hum data ko permanent storage (like .txt file) mein store kar sakte hain, ya wahan se read kar sakte hain.

File Handling Functions

Function Use

fopen() File ko open karne ke liye

fclose() File ko close karne ke liye

fprintf() File mein data likhne ke liye

fscanf() File se data read karne ke liye

fgetc() File se ek character read karne ke liye

fputc() File mein ek character likhne ke liye

File Open Modes

fopen("filename", "mode");

Mode Meaning

"r" Read Mode

"w" Write mode (overwrite if file exists)

"a" Append mode (data add hota hai)

"r+" Read + Write (file must exist)

"w+" Write + Read (file overwrite hoti hai)

"a+" Append + Read

Example: Write to a File

#include <stdio.h>

int main() {
  FILE *fp;
  fp = fopen("data.txt", "w"); // "w" se file write mode mein open hogi

  if (fp == NULL) {
    printf("File open nahi ho paayi!\n");
    return 1;
  }

  fprintf(fp, "Hello, ye file mein likha gaya hai!\n");
  fclose(fp); // File close karna zaroori hai

  printf("Data file mein successfully likh diya gaya.\n");
  return 0;
}

Example: Read from a File

#include <stdio.h>

int main() {
    FILE *fp;
    char ch;

    fp = fopen("data.txt", "r");

    if (fp == NULL) {
        printf("File read nahi ho paayi!\n");
        return 1;
    }

    printf("File content:\n");
    while ((ch = fgetc(fp)) != EOF) {
        putchar(ch);
    }

    fclose(fp);
    return 0;
}

Important Tips

• Har fopen() ke baad NULL check karna zaroori hai.
• fclose() se memory leak aur file corruption se bacha ja sakta hai.
• File ke path ka dhyan rakho – agar file same folder mein hai toh naam likhna kaafi hai.

Real-Life Uses of File Handling

• User input save karna (like login info, scores)
• Configuration files (like .ini, .json)
• Data logging (like error logs, transaction records)
• Simple databases (CSV or plain text format)

Conclusion

File management programming ko real-world ready banata hai. Agar aapko data ko save karna ya retrieve karna hai, toh file handling concepts ko achhi tarah samajhna zaroori hai.

Ab aap khud bhi ek file banakar usmein kuch likho aur fir read karo. Practice se hi mastery aati hai!

Bonus: Challenge for You!

• Ek program banao jo user se naam aur age le aur usse students.txt file mein store kare.
• Fir wahi file open karke sabhi student ke naam aur age read karo aur print karo.