Input a decimal data, convert to 8, using the sequence stack

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
// Sequence stack management structure :
typedef struct order_stack
{
    
	int  *stack;		// Stack space start address 
	int	 size;			// The size of the stack 
	int  top;			// To the top of the stack 
}Os, *P_os;

// Initialization of sequence stack 
P_os init_order_stack(int size)
{
    
	P_os os = (P_os)malloc(sizeof(Os));
	if (os != NULL)
	{
    
		os->stack = calloc(size, sizeof(int));
		os->size = size;
		os->top = 0;		// Generally, the top of the stack is initialized as  -1
	}
	return os;

}
// Stack in sequence 
bool in_stack(P_os os, int data)
{
    
	if (os == NULL || os->size == os->top+1)
	{
    
		printf(" The stack does not exist or is full \n");
		return false;
	}

	os->stack[os->top] = data;
	os->top++;
	return true;
}
// Sequential stack out 
bool out_stack(P_os os, int *data)
{
    
	if (os == NULL)
	{
    
		printf(" Stack does not exist \n");
		return false;
	}

	os->top--;
	*data = os->stack[os->top];
	printf("%d", *data);
	os->stack[os->top] = 0;	
}

void octal_show(P_os os,int n)// Convert to octal number 
{
    
	while(n>0)
	{
    
		in_stack(os,n%8);
		n/=8;
	}
	int m8;
	while(!(os->top==0))
	{
    
		out_stack(os,&m8);// The data is printed out of the stack , No need to print later 
	}
	printf("\n");
}

int main(int argc, char const *argv[])
{
    
	int n;
	P_os os = init_order_stack(10);
	printf(" Please enter a decimal integer ：\n");
	scanf("%d",&n);
	printf(" Convert to octal integer as ：\n");
	octal_show(os,n);
	return 0;
}

For reference only , It's convenient for you to check , If there is a mistake , Please comment and inform , thank you ！