C program to print contents in reverse order of a file

linux tac command implementation

//Write a program to print reverse content of file
#include <stdio.h>
#include <string.h>
 
int main(int argc, char *argv[])
{
    FILE *fp1;
     
    int cnt = 0;
    int i   = 0;
     
    if( argc < 2 )
    {
        printf("Insufficient Arguments!!!\n");
        printf("Please use "program-name file-name" format.\n");
        return -1;
    }
     
    fp1 = fopen(argv[1],"r");
    if( fp1 == NULL )
    {
        printf("\n%s File can not be opened : \n",argv[1]);
        return -1;
    }
     
    //moves the file pointer to the end.
    fseek(fp1,0,SEEK_END);
    //get the position of file pointer.
    cnt = ftell(fp1);
     
    while( i < cnt )
    {
        i++;
        fseek(fp1,-i,SEEK_END);
        printf("%c",fgetc(fp1));
    }
    printf("\n");
    fclose(fp1);
     
    return 0;
}

Actual file contents:
This is line1.
This is line2.
This is line3.
This is line4.
This is line5.
This is line6.

Output

Terminal command: ./prg2 file1.txt
.6enil si sihT
.5enil si sihT
.4enil si sihT
.3enil si sihT
.2enil si sihT
.1enil si sihT