Hello everyone, I am trying to devise a Binary Tree Representation of a Postfix Expression. I am sure I am in the right track, but there's just something wrong in my code which I cannot find.
I am just wondering if you guys can spot where I made my mistake. I would really appreciate your help.
I am using a Dev-C++ compiler.
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<conio.h>
struct node{
char item;
struct node* leftChild;
struct node* rightChild;
};
typedef struct node node;
node* root;
static node* stack[25];
static int stackPtr = -1;
node* pop(void)
{
return(stack[stackPtr--]);
}
void push(node* root)
{
stack[++stackPtr] = root;
}
void operator(char optr)
{
root = (node*)malloc(sizeof(node));
root->item = optr;
root->rightChild = pop();
root->leftChild = pop();
push(root);
}
void operand(char opnd)
{
root = (node*)malloc(sizeof(node));
root->item = opnd;
root->rightChild = NULL;
root->leftChild = NULL;
push(root);
}
void PostTraverse (node* root)
{
if (root->leftChild != NULL) {
PostTraverse (root->leftChild);
}
if (root->rightChild != NULL) {
PostTraverse (root->rightChild);
}
printf("%c ", root->item);
}
int main (void)
{
char postfix[] = "1 2 + 4 * 5 7 - +";
char *token;
int i = 0;
token = strtok(postfix, " ");
while (token != NULL) {
if(token !='('&& token !=')'&& token !='^'&& token !='*'&&
token !='/'&& token !='+'&& token !='-')
{
operand(token);
} else {
operator(token);
}
token = strtok(NULL, " ");
}
PostTraverse(stack);
printf("\n");
system("pause");
return 0;
}One problem I found is that the operator() function is like being ignored in the program and I don't know why that was happening. Any idea?
Thank you very much.
