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ftell() function in C language with Example

Here, we are going to learn about the ftell() function of library header stdio.h in C language with its syntax, example.
Submitted by Souvik Saha, on January 24, 2019

ftell() function in C

Prototype:

    long int ftell(FILE *filename);

Parameters:

    FILE *filename

Return type: long int

Use of function:

The ftell() function returns the current value of the file indicator pointer for the specified stream. In case of binary stream it returns the position in terms of bytes from the beginning. The prototype of the function ftell() is:

    long int ftell(FILE *filename);

When an error is occurred, it returns -1.

ftell() example in C

#include <stdio.h>
#include <stdlib.h>

int main()
{
    //Initialize the file pointer
    FILE* f;
    //Take a array of characters
    char ch[100];
    //Create the file for write operation
    f = fopen("includehelp.txt", "w");
    printf("Enter five strings\n");
    for (int i = 0; i < 4; i++) {
        //take the strings from the users
        scanf("%[^\n]", &ch);
        //write back to the file
        fputs(ch, f);
        //every time take a new line for the new entry string
        //except for last entry.Otherwise print the last line twice
        fputs("\n", f);
        //clear the stdin stream buffer
        fflush(stdin);
    }
    //take the strings from the users
    scanf("%[^\n]", &ch);
    fputs(ch, f);
    //close the file after write operation is over
    fclose(f);
    //open a file
    f = fopen("includehelp.txt", "r");
    printf("\n...............print the strings..............\n");
    while (!feof(f)) {
        //takes the first 100 character in the character array
        fgets(ch, 100, f);
        //and print the strings
        printf("%s", ch);
    }
    rewind(f);
    printf("\n...............print the position after print a strings ..............\n");
    fgets(ch, 100, f);
    printf("%s", ch);
    //print the current location
    printf("the file indicator position is - %d\n", ftell(f));

    //close the file
    fclose(f);

    return 0;
}

Output

C stdio.h Library Functions Programs »

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