Thread: I have a problem if FILEs

U like the smiley faces don't you?

Here is the solution you are searching for,
#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","wb");
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);
}
fclose(fp);

fp=fopen("struct.txt","rb");
while((fread(&r,sizeof(struct data),1,fp)) != 0)
{
printf("\nID:%d\t\tGPA:%d",r.id,r.gpa);
}
fclose(fp);

}

note: when you put new line (fprint(fp, "\n"); ) and you are not reading it back in the loading routine, you are destroying the aligment of the saved file structure.

the problem with the last entry displayed by the load routine caused by the fact that you check for the EOF (using feof), but in the last reading the fread havn't read the EOF yet, and in the next time the loop was running, fread red it and added it to the area pointed by the address of the struct, causing it to show bad results.

note: if you want the file to use older entrys, change the writing mode to ab (now it's wb).

also note: the code was tested with vc6, and it found working currectly.
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scanf("%d",&r->id);


Hi guys,
I was just wondering... for the above code, since r is already a pointer, why do you want the address of the pointer?

wouldn't it be better to have

scanf("%d",r->id);


your comments please

[QUOTE]Originally posted by talal*c

hello, infact there is nothing wrong with your code, if you use fread to read "struct.txt" u'll see that u can get what u've written..
but if u try to see the contents of "struct.txt" by external programs like notepad.exe instead of reading records by c code, u will see different characters, and this is natural.. because when u open a file the content of file is what meaning u get..


here is the code..

void writerec(struct data *r)
{
printf("ID : %d \n",r->id);
printf("GPA : %d \n",r->gpa);
}

main()
{
..... bla bla

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

fclose(fd);
getch();

.....
}

ohh than you vare mutch
Liran Oz Liran Oz Liran Oz Liran Oz Liran Oz Liran Oz Liran Oz
thank you

this problom was driving me crazy

thank you agen
and thanks avry budy<<<