Thread: I have a problem if FILEs

hello ther i am a new one here
I have a problem with files :
That i can't read and write to a file when the wreten item is
int or float (when i write ther comes charecters whit out meaning).
and when i write char it is very G D ...


please solve my problem
ofcours in C,,,

thank you,,,,

hello thank you for answering
and thos os the code useing fwrite.
i hope that you can help my....

PHP Code:

#include<stdio.h>
//-------------------------------------
struct data
{
    int id;
    int gpa;
};
//-------------------------------------
//-------------------------------------
void readrec(struct data *r)
{
    printf("\n Enter the ID No: ");
    scanf("%d",&r->id);
    printf("\n Enter the GPA: ");
    scanf("%d",&r->gpa);
}
//-------------------------------------
main()
{
    FILE *fp;
    struct data r;
    int ch=0;

    fp=fopen("struct.txt","a+");
    printf("\n Enter (1)to write. (0)to EXIT.");
    scanf("%d",&ch);
            while(ch!=0)
            {
                readrec(&r);
            
                fwrite(&r,sizeof(struct data),1,fp);
                    printf("\n Enter (1)to write. (0)to EXIT.");
                    scanf("%d",&ch);
            }
} 


2 know (I opend the file a,a+,w,w+,wb)but it did't work

Change the mode to "wb" and it will work. I suppose you could also use "ab", I think anyway, but the 'b' means binary.

The reason why you don't think it worked is because the numbers are in binary form in your datafile. Text characters appear the same in binary or text but numbers in binary when viewed in a text file look screwed up. Your program works, just change the mode in the fopen statement.

ok, this is my final program:

PHP Code:

#include<stdio.h>
//-------------------------------------
struct data
{
    int id;
    int gpa;
};
//-------------------------------------
//-------------------------------------
void readrec(struct data *r)
{
    printf("\n Enter the ID No: ");
    scanf("%d",&r->id);
    printf("\n Enter the GPA: ");
    scanf("%d",&r->gpa);
}
//-------------------------------------
main()
{
    FILE *fp;
    struct data r;
    int ch=0;

    fp=fopen("struct.txt","ab");
    printf("\n Enter (1)to write. (0)to EXIT.");
    scanf("%d",&ch);
            while(ch!=0)
            {
                readrec(&r);
            
                fwrite(&r,sizeof(struct data),1,fp);
                fprintf(fp,"\n");
                    printf("\n Enter (1)to write. (0)to EXIT.");
                    scanf("%d",&ch);
            }
            fclose(fp);

    fp=fopen("struct.txt","rb");
    while(!feof(fp))
    {
        fread(&r,sizeof(struct data),1,fp);
            printf("\nID:%d\t\tGPA:%d",r.id,r.gpa);
    }
    fclose(fp);

} 


when i input
id:1 gpa:1
the out put is
id:1 gpa:1
id:10 gpa:1
that what is in the file struct.txt----> (

).

That is correct.

I know in my exam i had 20/20 (FULL MARK).
but when i run the program it did't work eather???
the problem is still thir?



please help me!!!!

sorry the upper reply was me...

What problem? The program works correctly. I don't see any problem with it.

i do't see a problem to and so my Dr and so my frinds

******but it did't work******

please can you try to compile it and see ?
or give me a nother code from your self ?
please this is my only problem in the C lang
it drivs me crazy

I started smoking (just a jok)

please heeeeeeeelp me !!!!

Works fine.

feof doesn't work as you expect - it only returns TRUE when some other file reading function has also returned TRUE.

So

Code:

while(!feof(fp))

    {

        fread(&r,sizeof(struct data),1,fp);

            printf("\nID:%d\t\tGPA:%d",r.id,r.gpa);

    }

Should be

Code:

        while ( fread(&r,sizeof(struct data),1,fp) == 1 ) {
            printf("\nID:%d\t\tGPA:%d",r.id,r.gpa);
        }

Or you could just update your while loop to check the return result of fread, and only output information when it returns success...

my problem is still ther:::::::::::::::::::::::::::;


I wender if my windows xp that I ues is the problem????
coz xp is in java ? will it make sinc?

please help mt

i am a begener in c programing

my problem that i can't read write int, float, ...from file

the above program did't work>>
that is my problem...


abd for the xp micrpswft sed that it is wrten in java.