Thread: Assigning a pointer a value -- Still = 0?

I'm making an RPN calc (more specifically, one that mimics unix's dc), but I can't seem to get my newvalptr to not = 0 (This means that when it pushes the value onto the stack, it's 0, instead of the result of the operation).

The weird thing is that after the line newvalptr = &newval; I tried even putting in *newvalptr = 5, and printing it out. newvalptr was still = 0, but newval was = 5...it seems that no matter what, when it's pushed on to the stack it pushes 0 (but only after doing a computation, it pushes numbers onto the stack fine before it reaches an operation

Code:

#include <stdio.h>
#include <stdlib.h> //atoi()
#include <string.h>


void push( void **stack, void *value);
void *pop( void **stack );


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

//create stack
void *stringStack = NULL;


int *newvalptr = NULL;
int newval = 0;


//parse input

//NOTE: only works for 2 argument operations (2+2 =?)
for (int i = 1; i < argc; i++)
{ printf("Time.\n");

  if (*argv[i] == '+') 
  { 
  
    //bad idea...
    //newval = (int *) pop(&stringStack) + (int *) pop(&stringStack);
    
    char *val1 = pop(&stringStack);
    char *val2 = pop(&stringStack);
    
    printf("val1 = %d \n", atoi(val1));
    printf("val2 = %d \n", atoi(val2));
    
    newval = atoi(val1) + atoi(val2);
    
    newvalptr = &newval;
    
        
    //printf("newval is %d \n", *newvalptr);
    printf("newval is %d \n", newval);
    
    //push(&stringStack, newvalptr);
    push(&stringStack, &newvalptr);
        
  }

Here's my code for the stack struct, if needed:

Code:

/* STACK */
typedef struct node {
          void  *val;
   struct node  *next;
} Node;

Node *newNode( void  *newval, Node *succ )
{
   Node *new = malloc( sizeof(Node) );
   *new = (Node){ newval, succ };
   return new;
}
/* END STACK */


/* STACK METHODS */	

void push( void **stack, void *value)
{
   *stack = (void *) newNode( value, (Node *) *stack );
}

void *pop( void **stack )
{
   Node *top = (Node *) *stack;
   void *answer = top->val;
   *stack = top->next;
   free(top);
   return answer;
}
 /* END STACK METHODS */

Thanks!

> push(&stringStack, &newvalptr);
Try
push(&stringStack, newvalptr);

or even
push(&stringStack, &newval);