CODEWITHSUNDEEP
cpointersstruct
Tanner
Tanner

Reputation: 430

expected expression before 'struct'

I'm getting the error "expected expression before 'struct'" on the the first line in the function allocate() below. I cant figure out why.

I should say that I've been tasked to make this code work with the structure / function headers provided.

Any help is much appreciated!

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <assert.h>
#include <time.h>

struct student{
    int id;
    int score;
};

struct student* allocate(){
     /*Allocate memory for ten students*/
     struct student *stud =  malloc(10 * sizeof struct *student);
     assert (stud !=0);

     return stud;
}

void generate(struct student *students){
     /*Generate random ID and scores for ten students, ID being between 1 and 10, scores between 0 and 100*/
     srand(time(NULL));

     // Generate random ID's
     int i;
     for(i=0; i<10; i++){
        students[i].id = rand()*10+1;
     }

     //Generate random scores
     for(i=0; i<10; i++){
        students[i].score = rand()*10+1;
     }
}

void output(struct student* students){
     //Output information about the ten students in the format:

     int i;
     for(i=0; i<10; i++){
        printf("ID-%d Score-%d\n", students[i].id, students[i].score);
        }
}

void summary(struct student* students){
     /*Compute and print the minimum, maximum and average scores of the ten students*/
     int min = 100;
     int max = 0;
     int avg = 0;
     int i;
     for(i=0; i<10; i++){
        if(students[i].score < min){
            min = students[i].score;
        }
        if(students[i].score > max){
            max = students[i].score;
        }
        avg = avg + students[i].score;
    }
    avg = avg/10;
    printf("Minimum score is %d, maximum score is %d, and average is %d.", min, max, avg);

}

void deallocate(struct student* stud){
     /*Deallocate memory from stud*/
     free (stud);
}

int main(){
   struct student *stud = NULL;

    /*call allocate*/
    stud = allocate();

    /*call generate*/
    generate(stud);

    /*call output*/
    output(stud);

    /*call summary*/
    summary(stud);

    /*call deallocate*/
    deallocate(stud);

    return 0;
}

Upvotes: 4

Views: 46082

Answers (2)

autistic
autistic

Reputation: 15642

Your problem is in sizeof struct *student. When using the sizeof operator on a typename, you need to parenthesize the typename. In addition, as Jonathan Leffler identified in the comments to this answer, the placement of * in struct *student is erroneous, and the use of struct student * would be incorrect in the context of this code. Perhaps you meant: sizeof (struct student).

Alternatively, you could use sizeof on an expression, and you won't need the parenthesis. This would be preferable, because if you choose to change the type of stud then you won't need to replace an extra typename when you do so: struct student *stud = malloc(10 * sizeof *stud);

Upvotes: 1

Krishnabhadra
Krishnabhadra

Reputation: 34275

You may want to write

sizeof(struct student)

instead of 

sizeof struct *student

Upvotes: 10

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