C — How would I make my stack completely dynamic? [duplicate] - c

Question

This question already exists:
C- How can I push Strings to stack one element at a time?
Closed 7 years ago.
Currently my code uses a stack and pushes a user entered string into the stack one by one. However I would like to make it dynamic, what would I malloc/realloc, I know I'm missing something completely obvious but I guess I have tunnel vision... help?
#include <stdio.h>
#include <stdlib.h>
#define MAXSIZE 100
char a [MAXSIZE];
char * p = a;
int top = -1;
void push ( char n )
{
if ( top == 99)
{
printf( "stack overflow");
return;
}
top+=1;
a[top] = n;
}
/* Function to delete an element from the stack */
void pop(){
if(top == -1)
printf("Stack is Empty");
else
top-=1;
}
char *inputString(FILE* fp, size_t size){
//The size is extended by the input with the value of the provisional
char *str;
int ch;
size_t len = 0;
str = realloc(NULL, sizeof(char)*size);//size is start size
if(!str)return str;
while(EOF!=(ch=fgetc(fp)) && ch != '\n'){
str[len++]=ch;
if(len==size){
str = realloc(str, sizeof(char)*(size+=16));
if(!str)return str;
}
}
str[len++]='\0';
return realloc(str, sizeof(char)*len);
}
int balanced (char * m){
int size = sizeof(m);
int i, j;
for (i=0; i<=size; ++i){
push(m[i]);
}
}
int main(void){
char *m;
printf("input string : ");
m = inputString(stdin, 10);
printf("%s\n", m);
balanced(m);
int i;
for (i=0;i<=sizeof(a);++i){
printf("\n%c", a[i]);
}
free(m);
return 0;
}

Answer 1

If I understand your question properly, this is what you are supposed to do.
struct Stack
{
char c;
struct Stack *next;
}*stack = NULL;
char pop()
{
if(stack == NULL)
{
printf("Stack Underflow\n");
return NULL;
}
c = stack -> c;
struct Stack * temp = stack;
stack = stack -> next;
free(temp);
return c;
}
void push(char c)
{
struct Stack * temp = malloc(sizeof(struct Stack));
temp -> next = NULL;
temp -> c = c;
if (stack == NULL)
stack = temp;
else
{
temp -> next = stack;
stack = temp;
}
}