w + mode

The w+ mode in C is used to open a file for both reading and writing, with some specific features.

1. If the file does not exist, w+ creates a new file.
2. If the file already exists, the content of the file is erased (truncated to zero length).
3. You can both read from and write to the file.
4. The file pointer is placed at the beginning of the file.
5. Opening a file with w+ will truncate the file to zero length. This means all existing data in the file will be erased.

Example

#include<stdio.h>

#include<conio.h>

int main(){

   FILE *fp;

   char str[20];

   char ch;

   fp = fopen("D://program.txt", "w+");

   if (fp == NULL) 

    {

       printf("Error");

       exit(1);   

    }

    fputs("The correct place for easy learning",fp);

    rewind(fp);

    while(!feof(fp))

    {

     ch = fgetc(fp);

     printf("%c",ch);               

    }

    printf("\n Data written successfully");

    

 fclose(fp);

getch();

return 0;

}

Output