DPST1091 Revision Structs Sample Solutions

Download struct_create.c here, or copy it to your CSE account using the following command:

cp -n /import/reed/A/dp1091/public_html/24T3/activities/struct_create/struct_create.c .

Your task is to add code to this function in struct_create.c:

// create an instance of the struct and return a pointer to it
struct numbers *struct_create(int a, int b) {
    // PUT YOUR CODE HERE (you must change the next line!)
}

struct numbers {
    int first;
    int second;
};

struct_create should take two integers as input and return a pointer to a struct numbers variable that it has created. Its first input should be stored in the first field and its second input should be stored in the second field.

For example if the integers are:

int a = 1;
int b = 2;

and the function is called like this:

struct numbers* n = struct_create(a, b);

Assumptions/Restrictions/Clarifications.

struct numbers cannot be edited. It must be used as it is.

struct_create should call malloc() to allocate memory.

struct_create should not print anything. It should not call printf.

Your submitted file may contain a main function. It will not be tested or marked.

When you think your program is working you can use autotest to run some simple automated tests:

1091 autotest struct_create

#include <stdio.h>
#include <stdlib.h>

// Do not edit this struct. You may use it exactly as it is
// but you cannot make changes to it
struct numbers {
    int first;
    int second;
};

// create an instance of the struct and return a pointer to it
struct numbers *struct_create(int a, int b) {
    struct numbers *n = malloc(sizeof (struct numbers));
    n->first = a;
    n->second = b;
    return n;
}

// This is a simple main function which could be used
// to test your struct_create function.
// It will not be marked.
// Only your struct_create function will be marked.

int main(void) {
    int first = 1;
    int second = 2;
    
    struct numbers* n = struct_create(first, second);
    
    printf("%d, %d\n", n->first, n->second);
    return 0;
}