106 lines
2 KiB
C
106 lines
2 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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typedef struct doubleStack {
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int capacity;
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int top1;
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int top2;
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int *arr;
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} doubleStack;
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doubleStack *createStack(int capacity) {
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doubleStack *new = malloc(sizeof(doubleStack));
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new->capacity = capacity;
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new->top1 = -1;
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new->top2 = capacity;
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if (capacity <= 0) {
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return NULL;
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}
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new->arr = malloc(sizeof(int) * capacity);
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return new;
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}
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void removeStack(doubleStack *st) {
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free(st->arr);
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free(st);
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}
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void push(doubleStack *st, int in, int side) {
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// side == 0: top1
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// side == 1: top2
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if (st->top1 == st->top2 - 1) {
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printf("ERR: array is full\n");
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return;
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}
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if (side == 0) {
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st->top1++;
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st->arr[st->top1] = in;
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} else {
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st->top2--;
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st->arr[st->top2] = in;
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}
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}
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int top(doubleStack *st, int side) {
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if (side == 0) {
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return st->arr[st->top1];
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} else {
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return st->arr[st->top2];
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}
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}
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int isEmpty(doubleStack *st, int side) {
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if (side == 0) {
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return (st->top1 == -1);
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} else {
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return (st->top2 == st->capacity);
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}
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}
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void pop(doubleStack *st, int side) {
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if (!isEmpty(st, side)) {
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if (side == 0) {
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st->top1--;
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} else {
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st->top2--;
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}
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} else {
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printf("ERR: array is empty\n");
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}
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}
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int main(void) {
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doubleStack* test = createStack(5);
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push(test, 1, 0);
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printf("Top of left stack is %d\n", top(test, 0));
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push(test, 2, 0);
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printf("Top of left stack is %d\n", top(test, 0));
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push(test, 3, 0);
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printf("Top of left stack is %d\n", top(test, 0));
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push(test, 4, 0);
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printf("Top of left stack is %d\n", top(test, 0));
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push(test, 5, 0);
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printf("Top of left stack is %d\n", top(test, 0));
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push(test, 6, 0);
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printf("Top of left stack is %d\n", top(test, 0));
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pop(test, 0);
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push(test, 6, 0);
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printf("Top of left stack is %d\n", top(test, 0));
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pop(test, 0);
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pop(test, 0);
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push(test, 9, 1);
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printf("Top of right stack is %d\n", top(test, 1));
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push(test, 8, 1);
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printf("Top of right stack is %d\n", top(test, 1));
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removeStack(test);
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return 0;
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}
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