Thread: STACK/FIFO as a linked list

just was experimenting.. here is the code:

Code:

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

#define snapd(arg) printf(#arg " = %d\n", arg);
#define snapf(arg) printf(#arg " = %f\n", arg);

struct fifo 
{
    int data;
    struct fifo *next;
};

struct fifo *push(struct fifo *st, int value)
{
    struct fifo *newnode;

    if (st == NULL)
        {
        newnode = (struct fifo *)malloc(sizeof(struct fifo));
        newnode->data = value;
        newnode->next = NULL;
        return newnode;
        }

    newnode = (struct fifo *)malloc(sizeof(struct fifo));
    newnode->data = value;
    newnode->next = st;
    return newnode;

}

struct fifo *pop(struct fifo *st)
{
    struct fifo *top;

    if (st == NULL)
        {
        printf("The stack is empty!\n");
        return NULL;
        }

    top = st->next;
    free(st);
    return top;

}

void printstack(struct fifo *st)
{
    if (st == NULL)
        {
        printf("The stack is empty!\n");
        return;
        }

    do
        {
        printf("%d\n", st->data);
        st = st->next;
        }
    while (st);
}



int main (int argc, char *argv[])
{

    struct fifo *myfifo = NULL;
    int command, value;

    printf("FIFO/Stack implementation with linked list.\n");
    printf("1 - push value.\n");
    printf("2 - pop value.\n");
    printf("3 - print stack.\n");
    printf("4 - exit.\n");
    printf("Enter your command: ");


    for (;;)
        {

        scanf("%d", &command);

        switch (command)
            {
            case 1:
                {
                printf("Enter the value to push on to the stack: ");
                scanf("%d",&value);
                myfifo = push(myfifo, value);
                printf("Enter the next command: ");
                break;
                }

            case 2:
                {
                myfifo = pop(myfifo);
                if (myfifo != NULL) printf("The value is popped out of the stack\n");
                printf("Enter the next command: ");
                break;
                }

            case 3:
                {
                printf("The contains of the stack is:\n");
                printstack(myfifo);
                printf("====================================\n");
                printf("Enter the next command: ");
                break;
                }

            case 4:
                return 0;

            default:
                {
                printf("Wrong command!\n");
                printf("1 - push value.\n");
                printf("2 - pop value.\n");
                printf("3 - print stack.\n");
                printf("4 - exit.\n");
                printf("Enter your command: ");
                break;
                }

            }
        }

Your heading is confusing. Stacks and recursion calls are LIFO. ADTs like queues or FIFO.

ah..yeah i know its wrong... i mean Stack/LIFO... true...queues are FIFO yeah!