Usage of Sentinel Value

[ilkeamasya]

As you see at below I used "-1" as my sentinel value but my program wants the other 6 values i asked for in scanf too. How can i solve this problem? I just want the user to enter -1 and exit my loop. I would greatly appreciate for your help..
Regards..

#include <stdio.h>
#include <math.h> 
#include <ctype.h>

#define N 100
#define ISIMUZUN 15

  struct student{
  char name[ISIMUZUN];
  char surname[ISIMUZUN];
  int number;
  float final;
  float midterm;
  float hw1;
  float hw2;
  float grade;
  char *letter;
                };
int main(int argc, char *argv[])
{

  struct student info[N];
  int i=0, total=0,total2=0,j=0;
  double mean=0, stddvt=0, temp=0;
  int studentcounter=0,aacount=0,bacount=0,bbcount=0,cbcount=0,cccount=0,dccount=0,ddcount=0,ffcount=0,vfcount=0;
  float midtotal=0,midavr=0,fintotal=0,finavr=0,hw1total=0,hw1avr=0,hw2total=0,hw2avr=0;


    do{    printf("Please enter student's information with blanks between them\n");

    scanf( "%d %s %s %f %f %f %f", &info[i].number, info[i].name, info[i].surname, &info[i].midterm, &info[i].final, &info[i].hw1, &info[i].hw2   );
    info[i].grade = (info[i].final*0.4)+ (info[i].midterm*0.25)+ (info[i].hw1*0.15) + (info[i].hw2*0.20);
    if(info[i].number==-1)
    break;
    studentcounter=studentcounter+1;
    i++;
     }while  (info[i].number!=-1);

[gerard4143]

Don't request everything in one scanf call. Call scanf for your sentinel value the check the result and then call scanf for the remainder.

[ilkeamasya]

Don't request everything in one scanf call. Call scanf for your sentinel value the check the result and then call scanf for the remainder.

But i needed to have all information with blank space. Is there another way to do it as i wanted?

By the way, I can not print letter

char *letter;
if(info[i].grade >= (mean + 1.5*stddvt)){
    info[i].letter= "AA";

with

printf("%s\n",info[i].letter);

code. I thought using as a pointer would be better as you have said but can not print it out. Any idea about that?

[Banfa]

Calling scanf twice does not mean the user has to enter the data on more than one like. There is no implied reading of a new line character at the end of a scanf call.

scanf just requires whitespace between fields which is space, tab, newline, carriage return but it is not at all fussy about which ones it gets.

[ilkeamasya]

Thank you very much.. I think now my sentinel value works perfect. Do you have any idea about printing the pointer ?

[abhimanipal]

char *letter;
if(info[i].grade >= (mean + 1.5*stddvt)){
    info[i].letter= "AA";

This code is wrong. When you say char* letter you just have a pointer. For storing data the pointer has to point to some memory. Check out the function malloc

[ilkeamasya]

I see. Thanks for your replies. Everything is working in my code as it should. One quick question if i may :

printf("Student Number             Student Name           Grade   Letter\n");
printf("================  ==============================  =====   ======\n");

    	for(i=0;i<studentcounter;i++){    
	printf("%-18d%16s %-14s%7.2f%8s\n",info[i].number,info[i].name,info[i].surname,info[i].grade,info[i].letter);

I want this to look organized -aligned-. I can left align names but since all names have different number of characters the space between the name and the surname varies all the time. How can i align them?
regards..