Struct keyword inside a struct declaration

Question

This is from the following webpage: http://c.learncodethehardway.org/book/ex16.html

....deleted code

struct Person {
    char *name;
    int age;
    int height;
    int weight;
};

struct Person *Person_create(char *name, int age, int height, int weight)
{
struct Person *who = malloc(sizeof(struct Person));
assert(who != NULL);

who->name = strdup(name);
who->age = age;
who->height = height;
who->weight = weight;

return who;
}

[Rest of code not shown]

I am not able to understand the statement "struct Person *who = malloc(sizeof(struct Person));

This statement is inside struct Person *Person_create function. So what exactly is struct Person *who doing?

Piyush Vishwakarma · Accepted Answer · 2014-11-25 19:48:26Z

1

'who' is just a temporary pointer of type struct person that is pointed to the block of memory. So malloc(sizeof(struct Person) creates that block and assigns its address to 'who'. Now to access every element within this block, who->name will be a pointer the name element of that block,and so on. The pointer 'who' is returned at the end for any further operations of the same block.

answered Nov 25, 2014 at 19:48

Piyush Vishwakarma

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midor · Accepted Answer · 2014-11-25 19:36:24Z

0

Unlike in other languages, it is necessary to prefix a struct with the struct keyword every time unless you typedef the struct. Therefore struct Person *who is simply the declaration of a pointer with the name who to a struct Person.

answered Nov 25, 2014 at 19:36

midor

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eric_the_animal · Accepted Answer · 2014-11-25 19:39:56Z

0

malloc(sizeof(struct Person)) is allocating a memory block based on the size of struct 'Person' and returns a pointer to the beginning of the new memory block to *who.

answered Nov 25, 2014 at 19:39

eric_the_animal

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