2022_problem/infix_to_postfix.cpp at main · Dhruvk13/2022_problem · GitHub

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#include <bits/stdc++.h>
using namespace std;
struct Node
{
    char data;
    struct Node *next;
} *top = NULL;
void push(char x)
{
    struct Node *t;
    t = new Node;

    if (t == NULL)
        printf("stack is full\n");
    else
    {
        t->data = x;
        t->next = top;
        top = t;
    }
}
char pop()
{
    struct Node *t;
    char x = -1;

    if (top == NULL)
        printf("Stack is Empty\n");
    else
    {
        t = top;
        top = top->next;
        x = t->data;
        free(t);
    }
    return x;
}
void Display()
{
    struct Node *p;
    p = top;
    while (p != NULL)
    {
        printf("%d ", p->data);
        p = p->next;
    }
    printf("\n");
}
int isBalanced(char *exp)
{
    int i;

    for (i = 0; exp[i] != '\0'; i++)
    {
        if (exp[i] == '(')
            push(exp[i]);
        else if (exp[i] == ')')
        {
            if (top == NULL)
                return 0;
            pop();
        }
    }
    if (top == NULL)
        return 1;
    else
        return 0;
}
int outpre(char x)
{
    if (x == '+' || x == '-')
        return 1;
    else if (x == '*' || x == '/')
        return 3;
    else if (x == '^')
        return 6;
    else if (x == '(')
        return 7;
    else if (x == ')')
        return 0;
    return 0;
}
int inpre(char x)
{
    if (x == '+' || x == '-')
        return 2;
    else if (x == '*' || x == '/')
        return 4;
    else if (x == '^')
        return 5;
    else if (x == '(')
        return 0;
    return 0;
}
int isOperand(char x)
{
    if (x == '+' || x == '-' || x == '*' || x == '/' || x == ')' || x == '(' || x == '^')
        return 0;
    else
        return 1;
}
char *InToPost(char *infix)
{
    int i = 0, j = 0;
    char *postfix;
    int len = strlen(infix);
    postfix = new char[len + 2];

    while (infix[i] != '\0')
    {
        if (isOperand(infix[i]))
        {
            postfix[j++] = infix[i++];
        }
        else
        {
            if (infix[i] == ')')
            {
                postfix[j++] = pop();
                i++;
            }
            else
            {
                if (outpre(infix[i]) > inpre(top->data))
                    push(infix[i++]);
                else
                {
                    postfix[j++] = pop();
                }
            }
        }
    }
    while (top != NULL)
    {
        char l = pop();
        if (l == '(' || l == '#')
        {
            continue;
        }
        else
        {
            postfix[j++] = l;
        }
    }

    postfix[j] = '\0';
    return postfix;
}
int main()
{
    char *infix = "a+b*c-(d/e+f*g*h)";
    push('#');
    char *postfix = InToPost(infix);
    printf("%s ", postfix);
    return 0;
}