Segmenation Fault - Working on stack data structure - c

Question

I'm attempting to create a program that would allow the user to create a stack data structure using the push, pop, and peek command. However, I keep running into a segmentation fault whenever I try and use the push command! I have no idea why it's not working, because I made sure to use malloc on the stack structure. The peek and pop command are working (as far as I can tell). Any help??
#include<stdlib.h>
#include<stdio.h>
#include "stack.h"
int mainMenuChoice, pushValue;
void mainMenu() {
printf("\nEnter your option: \n");
printf("1. Push\n");
printf("2. Pop\n");
printf("3. Peek\n");
printf("4. Exit\n");
scanf("%d", &mainMenuChoice);
}
Stack * initializeStack() {
Stack *new_stack;
int capacity = 100;
new_stack = (Stack *)malloc(sizeof(Stack));
new_stack->items = (int *)malloc(sizeof(int)*capacity);
new_stack->size = 0;
return new_stack;
}
void push(Stack *new_stack, int item) {
new_stack->items[new_stack->size++] = item;
}
void pop(Stack *new_stack) {
if(new_stack->size == 0) {
printf("The stack is empty, you can't pop any items!\n");
} else {
new_stack->size--;
}
}
int peek(Stack *new_stack) {
if(new_stack->size == 0) {
printf("The stack is empty.\n");
} else {
return new_stack->items[new_stack->size-1];
}
}
void menuOptions(int option) {
Stack *new_stack = initializeStack();
if(option == 1) {
Stack *new_stack;
printf("Enter an element to push: ");
scanf("%d", &pushValue);
push(new_stack, pushValue);
mainMenu();
menuOptions(mainMenuChoice);
} else if(option == 2) {
pop(new_stack);
mainMenu();
menuOptions(mainMenuChoice);
} else if(option == 3) {
peek(new_stack);
mainMenu();
menuOptions(mainMenuChoice);
} else if(option == 4) {
printf("Exiting...\n");
exit(0);
} else {
printf("Invalid input, please try again!\n");
mainMenu();
menuOptions(mainMenuChoice);
}
}
void program() {
mainMenu();
menuOptions(mainMenuChoice);
}
Also, this is the how I've structured the stack:
typedef struct Stack {
int size;
int *items;
}Stack;
Thank you so much in advance, I appreciate it!

Answer 1

I've simplified things a bit. You were having too many recursive calls and new_stack was being redefined [but not reallocated]. You'll still have more work to do (e.g. peek returns a value, but pop does not)
Here's the code [please pardon the gratuitous style cleanup]:
#include <stdlib.h>
#include <stdio.h>
//#include "stack.h"
typedef struct Stack {
int size;
int *items;
} Stack;
int mainMenuChoice;
int pushValue;
Stack *top_stack;
void
mainMenu()
{
printf("\nEnter your option: \n");
printf("1. Push\n");
printf("2. Pop\n");
printf("3. Peek\n");
printf("4. Exit\n");
scanf("%d", &mainMenuChoice);
}
Stack *
initializeStack()
{
Stack *new_stack;
int capacity = 100;
new_stack = (Stack *) malloc(sizeof(Stack));
new_stack->items = (int *) malloc(sizeof(int) * capacity);
new_stack->size = 0;
return new_stack;
}
void
push(Stack *new_stack, int item)
{
new_stack->items[new_stack->size++] = item;
}
void
pop(Stack *new_stack)
{
if (new_stack->size == 0) {
printf("The stack is empty, you can't pop any items!\n");
}
else {
new_stack->size--;
}
}
int
peek(Stack *new_stack)
{
if (new_stack->size == 0) {
printf("The stack is empty.\n");
return -1;
}
else {
return new_stack->items[new_stack->size - 1];
}
}
void
menuOptions(Stack *new_stack,int option)
{
if (option == 1) {
printf("Enter an element to push: ");
scanf("%d", &pushValue);
push(new_stack, pushValue);
}
else if (option == 2) {
pop(new_stack);
}
else if (option == 3) {
peek(new_stack);
}
else if (option == 4) {
printf("Exiting...\n");
exit(0);
}
else {
printf("Invalid input, please try again!\n");
}
}
int
main()
{
top_stack = initializeStack();
while (1) {
mainMenu();
menuOptions(top_stack,mainMenuChoice);
}
return 0;
}