Stack using array

#include<stdio.h>

int s[100];
int stack_size=0;

void print_stack()
{
    printf("current stack : ");
    for(int i=0;i<stack_size;i++)
    {
           printf("%d ",s[i]);
    }
    printf("\n");
}

void push(int number)
{
    printf("-->push(%d)\n",number);

    //do push
    s[stack_size] = number;
    stack_size++;

    print_stack();
}

int pop()
{
    printf("-->pop()\n");
    int num;

    //do pop
    s[stack_size] = 0;
    stack_size--;

    print_stack();
    return num;
}


int main(){

    push(5);
    push(6);
    push(7);
    pop();
    push(4);
    pop();
    pop();

}