#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX 100

char change_postfix(char arr[MAX], char Queue[MAX]);
int calculate(unsigned stack2[MAX], char Queue[MAX]);
int count = 0;
int count2 = 0;
int count3 = 0;

int main(void){

	unsigned stack2[MAX] = { 0 };	//계산할때 char로 계산이 안되기 때문에 unsigned 사용
	char insert;
	char arr[MAX] = { 0 };
	char Queue[MAX] = { 0 };
	
	// 입력
	while (1){
		printf("식 입력");
		scanf("%s", &insert);
		if (insert == '='){
			break;
		}
		arr[count] = insert;
		count++;
	}

	//후위 표기법으로 변경
	change_postfix(arr, Queue);

	//후위 표기법 출력
	for(int i =0; i < count2; i++){
		printf("%c  ", Queue[i]);
	}
	printf("\n");

	//계산
	int result = calculate(stack2, Queue);

	//계산 결과값 출력
	printf("%d", result);
}

char change_postfix(char arr[MAX], char Queue[MAX]){

	int check = 0;
	int beforestack = 0;
	int gwalhocheck = 0;
	char stack[MAX] = { 0 };

	while(1){
		if( check == count){
			break;
		}
		if((arr[check] <= '9') && (arr[check]> '0')){
			Queue[count2] = arr[check];
			check++;
			count2++;
		}
		else if(arr[check] == '('){
			gwalhocheck++;
			check++;
			while(1){
				if(arr[check] == ')'){
					gwalhocheck--;
					check++;
					while(1){
						if(count3 == beforestack){
							break;
						}
						Queue[count2] = stack[count3 -1];
						count2++;
						count3--;
					}
					break;
				}
				if((arr[check] < 58) && (arr[check] > 48)){
					Queue[count2] = arr[check];
					check++;
					count2++;
					if( (stack[count3 -1] == '*') || (stack[count3 -1] == '/')){
						Queue[count2] = stack[count3 -1];
						stack[count3 -1] = NULL;
						count3 --;
						count2++;
					}
				}	
				else if((arr[check] == '+') || (arr[check] == '*') || (arr[check] == '-') || (arr[check] == '/')){
					stack[count3] = arr[check];
					beforestack = count3;
					count3++;
					check++;
				}
			}
		}
		else if((arr[check] == '+') || (arr[check] == '*') || (arr[check] == '-') || (arr[check] == '/')){
			stack[count3] = arr[check];
			count3++;
			check++;
		}

		if((Queue[count2-1] > 48) && (gwalhocheck == 0) && (count2 > 1)){
			if((arr[check] == '*') || (arr[check] == '/')){
				stack[count3] = arr[check];
				count3++;
				check++;
			}
			else{
				while(1){
					if(count3 == 0){
						break;
					}
					Queue[count2] = stack[count3 -1];
					count2++;
					count3--;
				}
			}
		}
	}
	return Queue[MAX];
}

int calculate(unsigned stack2[MAX], char Queue[MAX]){
	int cal1 = 0;
	int cal2 = 0;
	int count3 = 0;
	int check = 0;

	for(int i = 0; i < count2; i++){
		if((Queue[i] <= '9') && (Queue[i]> '0')){
			stack2[count3] = Queue[i];
			count3++;
		}else if(((Queue[i] == '+') || (Queue[i] == '*') || (Queue[i] == '-') || (Queue[i] == '/'))){
			count3--;
			cal1 = stack2[count3] -48;
			stack2[count3] = NULL;
			count3--;
			cal2 = stack2[count3] -48;
			stack2[count3] = NULL;
			if(Queue[i] == '+'){
				stack2[count3] = (cal1 + cal2) + 48;
				count3++;
			}else if(Queue[i] == '*'){
				stack2[count3] = (cal1 * cal2) + 48;
				count3++;
			}else if(Queue[i] == '/'){
				stack2[count3] = (cal1 / cal2) + 48;
				count3++;
			}else if(Queue[i] == '-'){
				stack2[count3] = (cal1 - cal2) + 48;
				count3++;
			}
		}
	}
	int result = stack2[0] - 48;
	return result;
}