passing struct to function help

Im trying to pass elements of a structure to a function (call by reference)

This code suppose to work like this:
Enter students name and Points
then calculate points to grade in a function.

:confused:

Code:

---


#include<stdio.h>


void calculate (struct student *, struct student *);

int main (void)
{
       
        struct student
        {
                char name[30];
                float points;
                int grade;
        }stud[3];

       
        int i;
        for (i=1; i<=3; i++)
        {
                printf("%d.name->", i);  scanf( "%s", &stud[i].name );
                printf("points->");  scanf( "%f", &stud[i].points);
                calculate ( &stud[i], &stud[i] );
        }
        return 0;
}

void calculate ( struct student *nname, struct student *pnt )
{
    int grade;
    grade = ( (*pnt).points < 50 ? 5  :  4-(  (int)(*pnt).points - 50 / 15 )  );
        printf("\n%s´s grade is  %d", (*nname).name, grade);
}

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> for (i=1; i<=3; i++)
An array of 3 elements is indexed using for (i=0; i<3; i++)

> grade = ( (*pnt).points < 50 ? 5 : 4-( (int)(*pnt).points - 50 / 15 ) );
1. Use pnt->points in place of (*pnt).
It's less error prone.
2. Use if ( ) else to make your meaning clearer than the ?: operator

Also you only need to pass the parameter once to access all members of a structure

okay, I made some changes to make it more readable
my compiler gives me several errors and warnings
like unknown field etc

Code:

---

#include<stdio.h>


void calcu (struct student* );

int main (void)
{

        struct student
        {
                char name[30];
                float points;
                int grade;
        }stud[3];


        int i;
        for (i=0; i<3; i++)
        {
                printf("%d.name->", i);  scanf( "%s", &stud[i].name );
                printf("points->");  scanf( "%f", &stud[i].points);
                calcu ( &stud[i] );
        }
        return 0;
}

void calcu ( struct student *ptrstudent )        /* result: 5->"F"  4->"D"  3->"C"  2->"B" 1->"A" */
{
    int result;
        if (ptrstudent->points < 50)
        {
                result=5;
                printf("\n%s failed with a %d in his C test", ptrstudent->name, result);
    }
        else
        {
                result= ( (int)ptrstudent->points - 50 / 15 );
            printf("\n%s got a %d in his C test", ptrstudent->name, result);
}

---

Quote:

---

Originally Posted by staticalloc

okay, I made some changes to make it more readable
my compiler gives me several errors and warnings
like unknown field etc

---

Your struct student definition is made within the main function. As such, its scope is limited to the main function. Move the definition of that struct outside of main.

Code:

---

#include<stdio.h>

struct student
{
    char name[30];
    float points;
    int grade;
};

void calcu (struct student* );

int main (void)
{

    struct student stud[3];

    int i;
    for (i=0; i<3; i++)
    {
        printf("%d.name->", i);  scanf( "%s", &stud[i].name );
        printf("points->");  scanf( "%f", &stud[i].points);
        calcu ( &stud[i] );
    }
    return 0;
}

void calcu ( struct student *ptrstudent )        /* result: 5->"F"  4->"D"  3->"C"  2->"B" 1->"A" */
{
    int result;
    if (ptrstudent->points < 50)
    {
        result=5;
        printf("\n%s failed with a %d in his C test", ptrstudent->name, result);
    }
    else
    {
        result= ( (int)ptrstudent->points - 50 / 15 );
        printf("\n%s got a %d in his C test", ptrstudent->name, result);
    }
}

---

I did not check for other problems, except for the missing } marked above (typo?)

THANKS! I changed the code as you said and it works.

Code:

---

#include<stdio.h>

struct student
        {
                char name[30];
                float points;
                int grade;
        };

void calcu (struct student* );

int main (void)
{

        struct student stud[3];


        int i;
        for (i=0; i<3; i++)
        {
                printf("\n%d.name->", i);  scanf( "%s", &stud[i].name );
                printf("points->");  scanf( "%f", &stud[i].points);
                calcu ( &stud[i] );
        }
        return 0;
}

void calcu ( struct student *ptrstudent )
                                            /* result: 5->"F"  4->"D"  3->"C"  2->"B" 1->"A" */
{
    int result;
        if (ptrstudent->points < 50)
        {
                result=5;
                printf("\n%s failed with a %d in his C test",ptrstudent->name, result);
    }
        else
        {
                result= (4- ( (int)ptrstudent->points - 50 )/ 15 );
            printf("\n%s got a %d in his C test", ptrstudent->name, result);
    }
}

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