C rename remove fopen

#include <stdio.h>

int main ()
{

    char filename[] = "file.txt";
    FILE * fp ;
    fp = fopen(filename, "r");
    if(fp == NULL)
    {
      printf("This file NOT exists");
          return 0;
    }
    else
    {
        fp = fopen(filename, "r");
        if(fp == NULL)
        {
            printf("This file is exists and can not reading 
");   
        }          
        else 
        {
            printf("This file is exists and can reading ");   
        }
    } 

    int ret;
    char oldname[] = "file.txt";
    char newname[] = "newfile.txt";

    ret = rename(oldname, newname);

    if(ret == 0) 
    {
        printf("File renamed successfully
");

    }
    else 
    {
        printf("Error: unable to rename the file");
    }

    fclose(fp);
    ret = 0;
    ret = remove(newname);
    if(ret == 0) 
    {
        printf("File deleted successfully");
    }
    else 
    {
        printf("Error: unable to delete the file");
    }

    return(0);
}