How to create a struct on the stack in C? - c

Question

I understand how to create a struct on the heap using malloc. Was looking for some documentation regarding creating a struct in C on the stack but all docs. seem to talk about struct creation on heap only.

Answer 1

The same way you declare any variable on the stack:
struct my_struct {...};
int main(int argc, char **argv)
{
struct my_struct my_variable; // Declare struct on stack
.
.
.
}

Answer 2

To declare a struct on the stack simply declare it as a normal / non-pointer value
typedef struct {
int field1;
int field2;
} C;
void foo() {
C local;
local.field1 = 42;
}

Answer 3

an answer to 17.4 Extra Credit (in Zed's book "Learn C the Hard Way") using functions
#include <stdio.h>
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;
who.name = name;
who.age = age;
who.height = height;
who.weight = weight;
return who;
}
void Person_print(struct Person who)
{
printf("Name: %s\n", who.name);
printf("\tAge: %d\n", who.age);
printf("\tHeight: %d\n", who.height);
printf("\tWeight: %d\n", who.weight);
}
int main(int argc, char *argv[])
{
// make two people structures
struct Person joe = Person_create("Joe Alex", 32, 64, 140);
struct Person frank = Person_create("Frank Blank", 20, 72, 180);
//print them out and where they are in memory
printf("Joe is at memory location %p:\n", &joe);
Person_print(joe);
printf("Frank is at memory location %p:\n", &frank);
Person_print(frank);
// make everyone age 20 and print them again
joe.age += 20;
joe.height -= 2;
joe.weight += 40;
Person_print(joe);
frank.age += 20;
frank.weight += 20;
Person_print(frank);
return 0;
}

Answer 4

I got it to work this way:
#include <stdio.h>
struct Person {
char *name;
int age;
int height;
int weight;
};
int main(int argc, char **argv)
{
struct Person frank;
frank.name = "Frank";
frank.age = 41;
frank.height = 51;
frank.weight = 125;
printf("Hi my name is %s.\n", frank.name);
printf("I am %d yeads old.\n", frank.age);
printf("I am %d inches tall.\n", frank.height);
printf("And I weigh %d lbs.\n", frank.weight);
printf("\n-----\n");
struct Person joe;
joe.name = "Joe";
joe.age = 50;
joe.height = 93;
joe.weight = 200;
printf("Hi my name is %s.\n", joe.name);
printf("I am %d years old.\n", joe.age);
printf("I am %d inches tall.\n", joe.height);
printf("And I weigh %d lbs.\n", joe.weight);
return 0;
}