a + mode

 In C, the a+ mode is used for file handling and stands for "append and read." When you open a file in a+ mode, you can do the following:

• Append Data: You can write data to the end of the file. If the file does not exist, it will be created.
• Read Data: You can also read data from the file, starting from the beginning.

Example

#include<stdio.h>

#include<conio.h>

int main(){

   FILE *fp;

   char ch;

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

   if (fp == NULL) 

    {

       printf("Error");

       exit(1);   

    }

    fputs("Welcome to my Blog",fp);

    rewind(fp);

    while(!feof(fp))

    {

     ch = fgetc(fp);

     printf("%c",ch);               

    }

    printf("\n Append Done successfully");

    

 fclose(fp);

getch();

return 0;

}

Output