Thread: Multiple inputs separated by EOF

Seriously... I'm not easily annoyed, but this is ridiculous. You're ignoring everything everyone is telling you.

ctrl+z may or may not make an EOF character, that's not the point.

The point is, scanf returns the number of items read, not EOF.

This is like the story of the guy who went out with a million different girls once and never again and said, "I don't know what's wrong with them," after a million, you'd think you would realize the problem is with you. I had to clean that up to make it PG-13 so if it doesn't make much sense forgive me.

You've got ~10 people in ~30 threads telling you the same thing over and over again. Eventually you're going to annoy them to the point where they stop caring.

EDIT: EOF byte
Windows: CTRL+Z
*nix: CTRL+D

In the C Standard Library, the character reading functions such as getchar return a value equal to the symbolic value (macro) EOF to indicate that an end-of-file condition has occurred. The actual value of EOF is system-dependent (but is commonly -1, such as in glibc) and is unequal to any valid character code. Block-reading functions return the number of bytes read, and if this is fewer than asked for, then the end of file was reached.

> Why doesn't the control enter the second while loop
Because the EOF you signalled to end the first loop hasn't gone away by the time you hit the second loop - so it will exit immediately because the stdin stream is still in the end of file state.

Perhaps something like
clearerr(stdin);

Or better, separate input from conversion, and get rid of all those horrid fflush() calls.

Code:

#include<stdio.h>


int main(void)
{
    struct
    {
        int accno;
        char tt;    //!! you can't store a string here
        float amt;
    }x;

    struct
    {
        int accno;
        char name[30];
        float bal;
    }y;
    char buff[BUFSIZ];
    FILE *fa,*ft;

    if((fa=fopen("acc.txt","wb+"))==NULL)
        printf("Unable to open");
    if((ft=fopen("trans.txt","wb+"))==NULL)
        printf("Unable to open");

    printf("Enter elements for acc.txt (accno, name, bal)\n");
    while ( fgets( buff, sizeof(buff), stdin) != NULL ) {
      if ( sscanf(buff,"%d %s %f",&y.accno,y.name,&y.bal)==3) {
        fwrite(&y,sizeof(y),1,fa);
      } else {
        break;
      }
    }

    printf("\nEnter contents for trans.txt(accno, tt, amt)\n");
    while ( fgets( buff, sizeof(buff), stdin) != NULL ) {
      if ( sscanf(buff,"%d %s %f",&x.accno,&x.tt,&x.amt) == 3 ) {
        fwrite(&x,sizeof(x),1,ft);
      } else {
      }
    }

    fclose(fa);
    fclose(ft);

    return 0;
}

Originally Posted by andrew89

Seriously... I'm not easily annoyed, but this is ridiculous. You're ignoring everything everyone is telling you.

ctrl+z may or may not make an EOF character, that's not the point.

The point is, scanf returns the number of items read, not EOF.

This is like the story of the guy who went out with a million different girls once and never again and said, "I don't know what's wrong with them," after a million, you'd think you would realize the problem is with you. I had to clean that up to make it PG-13 so if it doesn't make much sense forgive me.

You've got ~10 people in ~30 threads telling you the same thing over and over again. Eventually you're going to annoy them to the point where they stop caring.

EDIT: EOF byte
Windows: CTRL+Z
*nix: CTRL+D

In the C Standard Library, the character reading functions such as getchar return a value equal to the symbolic value (macro) EOF to indicate that an end-of-file condition has occurred. The actual value of EOF is system-dependent (but is commonly -1, such as in glibc) and is unequal to any valid character code. Block-reading functions return the number of bytes read, and if this is fewer than asked for, then the end of file was reached.

I could't understand, were you trying to tell me that scanf should not be used to return EOF? or were you trying to tell jim that scanf could also return EOF and not just the number of characters read? Cause if you were talking to jim then I want to ask why the following code teriminates after going through the second while loop only once??

Code:

#include<stdio.h>

int main()
{
	FILE *ft;
	struct
	{
		int i;
		char c;
		float d;
	}a,b;


	ft=fopen("something.txt","wb+");

	printf("Enter some random contents (int followed by char followed by float)\n");
	
	while((scanf("%d %c %f",&a.i,&a.c,&a.d))!=EOF)
		fprintf(ft,"%d %c %f",a.i,a.c,a.d);

	printf("\n");
	
	rewind(ft);

	while(fscanf(ft,"%d %c %f",&b.i,&b.c,&b.d)!=0)
		printf("%d %c %f\n",b.i,b.c,b.d);
		
	fclose(ft);
}

Originally Posted by juice

why the following code teriminates after going through the second while loop only once?

When asking such a question in which the program accepts external input, you should also state what was the given input, the expected output and the actual output.