View difference between Paste ID: uGAK7mjy and WEDwmWF5

 #define _CRT_SECURE_NO_WARNINGS
 #include <stdio.h>
 #include <stdlib.h>
 #include <iostream>
 #include <string.h>
 #include <ctype.h>
 
 #define SIZE 100
 
 char* POST_IN_INFIC(char*);
 int calculator(char*);
 void Infic_in_Post(char* s);
 
 struct list_t {
 	char data;
 	list_t *next;
 	list_t *prev;
 };
 
 list_t *head, *tail;
 int n;
 
 void Push(char);
 void Pop(void);
 void Del(void);
 void Init(void);
 void Show(void);
 bool Empty(void);
 void Find(char,char);
 
 
 enum CHOICE {	// Выбор пользователя
 	QUIT = 0,
 	INFICINPOST,
 	CALCULATOR,
 	OTHER
 };
 
 CHOICE DoMenu(void);
 
 int main()
 {
 	freopen("err.txt", "w", stderr);
 	head=NULL;
 	char* s;
 	s=(char*)malloc(100*sizeof(char));
 	int choice = -1;
 
 	while (choice != QUIT) {
 		choice = DoMenu();
 
 		switch(choice) {
 		case INFICINPOST:
 			Init();
 			scanf("%s", s);
 			Infic_in_Post(s);
 			break;
 		case CALCULATOR:
             scanf("%s", s);
             calculator(s);
 		default:
 			break;
 		}
 	}
 	return 0;
 }
 
 CHOICE DoMenu(void)
 {
 	CHOICE choice;
 
 	printf(	"\nMenu\n"
 			"\t%d quit\n"
 			"\t%d infic->post\n"
 			"\t%d calculator\n"
 			"Enter new line: ",
 			QUIT, INFICINPOST, CALCULATOR);
 
 	scanf("%d", (int *)&choice);
 
 	switch (choice) {
 	case QUIT:
 	case INFICINPOST:
 	case CALCULATOR:
 		return choice;
 	default:
 		return OTHER;
 	}
 
 	return OTHER;
 }
 
 
 int PriorityComp(char a, char b)
 {
 	switch (a) {
 	case '(': case ')':
 		a = 0;
 		break;
 	case '+': case '-':
 		a = 1;
 		break;
 	case '*': case '/':
 		a = 2;
 		break;
 	default:
 		a = 3;
 		break;
 	}
 
 	switch (b) {
 	case '(': case ')':
 		b = 0;
 		break;
 	case '+': case '-':
 		b = 1;
 		break;
 	case '*': case '/':
 		b = 2;
 		break;
 	default:
 		b = 3;
 		break;
 	}
 
 	return a - b;
 }
 
 void Infic_in_Post(char* s)
 {	list_t *p;
 	int j;
 	unsigned int len = strlen(s);
 	Init();
 
 	for (unsigned int i = 0; i < len; i++) {
 		std::cerr << i << ") " << s[i] << std::endl;
 
 		if (s[i] >= '0' && s[i] <= '9') {
 			printf("%c", s[i]);
 			if (i == len - 1 || (i < len - 1 && (s[i + 1] < '0' || s[i + 1] > '9'))) printf(" ");
 		}
 		else if (s[i] == '(') {
 			Push(s[i]);
 		} else if (s[i] == ')') {
 			while (!Empty() && head->data != '(')
 				Pop();
 			Pop();
 		} else if (s[i]=='^') {
 			Push(s[i]); j = i+1;
 			while (j < len && s[j]<='9' && s[j]>='0') {
 				printf("%c", s[j]); j++;}
 			i = j - 1;
 			Pop();
 		}
 		else if (s[i]==' ')
 			printf(" ");
 		else {
 			if (Empty()) Push(s[i]);
 			else {
 				while (head!=NULL)
 					if (PriorityComp(head->data, s[i]) >= 0) Pop(); else break;
 				Push(s[i]);
 			}
 		}
 
 
 		/*else if (s[i]=='+' || s[i]=='-') {
 			Find('*','/');
 			Find ('+', '-');
 			Push (s[i]);
 		} else if (s[i]=='*' || s[i]=='/') {
 			Find ('*', '/');
 			Push (s[i]);
 		} */
 
 	}
 	while (!Empty()) Pop();
-	Del();
+
 
 int calculator(char* s)
 {
 	int j;
 	unsigned int len = strlen(s);
 
 	head->data=-1;
 	head->next->data=-1;
 
 	for (unsigned int i=0; i<len; i++) {
 	    if (s[i]=='+') head->data=(int)head->data+(int)head->next->data;
         else if (s[i]=='-') head->data=(int)head->data-(int)head->next->data;
         else if (s[i]=='*') head->data=(int)head->data*(int)head->next->data;
         else if (s[i]=='/') head->data=(int)head->data/(int)head->next->data;
         else if (s[i]=='^') head->data=(int)head->data^(int)head->next->data;
         else if (s[i]<='9' && s[i]>='0') {
 			j=i--;
 	        if (s[j]==' ') {
 				if (head->data!=(-1))
 	                head->next->data=(int)s[i];
 	            else head->data=(int)s[i];
 	        } else if (head->next->data!=-1)
 				head->data=head->data*10+(int)s[i];
 			else
 				head->next->data=head->next->data*10+(int)s[i];
 		}
 	}
 	return head->data;
 }
 
 bool Empty(void)
 {
 	if (n == 0)
 		return true;
 	else
 		return false;
 }
 
 void Push(char d)
 {
 	list_t *ins;
 
 	ins = (list_t*)malloc(sizeof(list_t));
 	ins->data = d;
 	ins->prev = NULL;
 
 	if (Empty()) {
 		ins->next = NULL;
 
 	} else {
 		ins->next = head;
 
 	}
 	++n; head = ins;
 }
 
 void Pop()
 {
 	char d;
 
 	if (head == NULL) return;
-	if (head == NULL)
+
 	if (n == 1) {
 		d = head->data;
 		free(head);
 		head = NULL;
-		//free(head);
+
 			printf("%c ", d);
 	} else {
 		d = head->data;
 		head = head->next;
 		free(head->prev);
 		head->prev = NULL;
 
-		//free(head->prev);
+
 			printf("%c ", d);
 	}
 	--n;
 }
 
 void Init(void)
 {
 	head = NULL;
 	n = 0;
 }
 
 void Show(void)
 {
 	list_t *p;
-void Del(void)
+
 		fprintf(stderr, "Steck is empty!\n");
-	return;
+
 	}
-	if (n == 1)
+
-		printf("%c", head->data);
+
 	printf("\n");
-	for (p = head->next; p != NULL; p = p->next)
+
-		{printf("%c", p->prev->data);
+
-		free(p->prev);}
+
 {
 	list_t *p;
 	p = head;
 	while (p!=NULL)
 	{
 		if (p->data==a || p->data==b)
 			printf("%c", p->data);
 		p=p->next;
 	}
 }