Thread: Strange characters and spaces in file when I write a structure in it.

I am writing a structure to a file. Program compiled and executes successfully. In file, I get strange spaces and some character(not even on keyboard), including the structure.. Meanwhile when I read the file on console, I get correct output(the structures I tried to write in file).

Code:

// C program for writing  
// struct to file 
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 

// a struct to read and write 

struct person  
{ 
    int id; 
    char fname[20]; 
    char lname[20]; 
}; 

int main () 
{ 

    FILE *outfile; 

    // open file for writing 

    outfile = fopen ("person.txt", "w"); 

    if (outfile == NULL) 
    { 
        printf(stderr, "\nError opening file\n"); 
        exit (1); 
    } 

    struct person input1 = {1, "rohan", "sharma"}; 

    struct person input2 = {2, "mahendra", "dhoni"}; 

    // write struct to file 

    fwrite (&input1, sizeof(struct person), 1, outfile); 

    fwrite (&input2, sizeof(struct person), 1, outfile); 

    if(fwrite != 0)  
        printf("contents to file written successfully !\n"); 

    else 
        printf("error writing file !\n"); 

    // close file 

    fclose (outfile); 

     //To read from file
FILE * infile = fopen("person.txt");
struct person input;

if(infile==NULL)
{
      printf("Error opening file!\n");
      exit(1);
}

//read file contents till end of file
while (fread(&input,sizeof(struct person),1,infile)
        printf("\nid = %d. name = %s %s\n",input.id,input.fname,input.lname);

fclose(infile);

    return 0; 
}

When I open file, I get these;
" rohan shama sc mahen dhoni"
(Without the quotes, where sc = strange character not even on my keyboard)
Please help, I'm a noob in this site.. thnks

P.S. this code was gotten from a website geeksforgeeks.com

Originally Posted by SergeP

Meanwhile when I read the file on console, I get correct output(the structures I tried to write in file).

Then there's no problem. You're using fwrite to write a binary representation of the struct person object to file, so when you open the file as if it were a text file, you might find some unusual output, but that's just the binary representation being misinterpreted as text. So, nothing to worry about. If you do want to open the file in an editor, open it in a hex editor.

That said, you're not checking for successful fwrite correctly: check the return value of the fwrite calls, not the fwrite function converted to a function pointer.

Originally Posted by SergeP

And is there a way to actually write the text (not the binary representation) i.e an alternative to fwrite?

Of course. You just need to decide on what you want the output to look like, and if you intend to read programmatically from file, you need to decide on an output format that can be read like that.

If she's the one answering, it's probably the best there is in the thread, just saying. Also, no, there is no way, not that I know of, to mark someone's response the best (in case you were thinking you could vote on others' answers like on StackOverflow).