Newbie question - struct & arrays

I am working on a homework assignment (a simple name and grade sorting program) but I am obviously missing something and am not seeing it.

Code:

---

#include <iostream>
#include <stdlib.h>
#include <string.h>
#define MAX 25
#define MAXN 10

using namespace std;

int nst;
struct NGrade {
      char name[MAX];
      int grade;   
};


int main(){

   
cout << "How many students do you want to process?" << endl;
cin >> nst;   

struct Ngrade grades[MAXN];

int i;
for(i=0; i < nst; i++)
{
    cout << "Enter name for student #" << nst << endl;       
    //cin >> grades[nst].name;       
   
    cout << "Enter grade for student #" << nst << endl;       
    //cin >> grades[nst].grade;   
}

    cout << endl;
    system("PAUSE");
    return EXIT_SUCCESS;
}

---

The error I get is:

Code:

---

22 D:\Dev-Cpp\grade2\main.cpp elements of array `Ngrade grades[10]' have incomplete type
22 D:\Dev-Cpp\grade2\main.cpp storage size of `grades' isn't known

---

Ideally I had wanted to set it up so that the array quantity (number of names and grades) in the structure was determined by the user at runtime but I can't seem to get it to take a predetermined number of items.

Simply put I don't understand why it doesn't like my array declaration.


Thanks in advance from the frustrated and confused,
n3m0

>int nst;

try to avoid global variables

>struct Ngrade grades[MAXN];

That doesnt look right to me. C++ uses classes over structs really.
Anyway, why would you declare Ngrade again after you have it defined outside main?

Code:

---

#include <iostream>
#include <stdlib.h>
#include <string.h>
#define MAXN 10

using namespace std;

int nst;
struct NGrade {
      char name[MAX];
      int grades;
};


int main(){

   
cout << "How many students do you want to process?" << endl;
cin >> nst;   

NGrade student;

student.grades;
student.name;

int i;
for(i=0; i < nst; i++)
{
    cout << "Enter name for student #" << nst << endl;       
    cin >> student.grades;
   
    cout << "Enter grade for student #" << nst << endl;       
    cin >> student.name;
};

    cout << endl;
    system("PAUSE");
    return EXIT_SUCCESS;
}

---

Here i had to change alot but this works, from what i could see you struct syntax was incorrect, you should have a look at how a structure is constructed, don't just take just take my advice tho.

Thank you. I did have to do some juggling tho' ;)

Here's what I have now (thanks again :D ):

Code:

---

#include <iostream>
#include <stdlib.h>
#include <string.h>
#define MAX 10
#define MAXN 10

using namespace std;

int nst;
struct NGrade {
      char name[MAX];
      int grades;
};


int main(){

   
cout << "How many students do you want to process?" << endl;
cin >> nst;   

NGrade student[nst];

student[nst].name;
student[nst].grades;


int i;
for(i=0; i < nst; i++)
{
    cout << "Enter name for student #" << i+1 << endl;       
    cin >> student[i].name;
   
    cout << "Enter grade for student #" << i+1 << endl;       
    cin >> student[i].grades;
};

    cout << endl;
    system("PAUSE");
    return EXIT_SUCCESS;
}

---

Your still using global varialbles. 'nst' can be moved inside the main function to make
it local.
Why is there a semi-colon after the for loop block?

Quote:

---

Originally Posted by swgh

Your still using global varialbles. 'nst' can be moved inside the main function to make
it local.
Why is there a semi-colon after the for loop block?

---

The semi-colon was my fault, does't it make a difference (I'm just curious) it works without but if ou do put it in what happens?

Quote:

---

student[nst].name;
student[nst].grades;

---

1. do nothing
2. access array of students outside its bounds - valide indexes are from 0 till nst-1


3. You don't check nst value entered by the user. What will happen if he will press 0 or -1 or 100000000 or 1.3 or 'y'? Have you checked your program with all this replies?

4. why do you need <string.h> ?