Competitive-Programming/Equation190.cpp at master · srinivas9804/Competitive-Programming · GitHub

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#include <iostream>
#include <cstring>
#include <string>
#include <stack>
#include <iomanip>
using namespace std;

int main() {
	int n = 0;
	int ctr = 0;
	string str;
	getline(cin, str);
	n = str[0] - '0';
	getline(cin, str);
	for (int i = 0; i < n; i++) {
		getline(cin, str);
		string postfix;
		stack <char> s;
		while (2>1) {
			if (str[0] == '\n' || str[0]=='\0')
				break;
			if (str[0] >= '0'&&str[0] <= '9') {
				postfix += str[0];
			}
			else if (str[0] == '+' || str[0] == '*' ||str[0] == '/' || str[0] == '-') {
				if (s.empty()) {//stack is empty
					s.push(str[0]);
				}
				else {
					char c;
					if (!s.empty())
						c = s.top();
					if (((str[0]=='*'||str[0]=='/') && (c!='*'&& c!= '/'))||((str[0] == '+'||str[0] == '-')&&(c != '*'&& c != '/' && c!='+' && c!='-'))) {
						s.push(str[0]);
					}
					else {
						postfix += c;
						if (!s.empty())
							s.pop();
						continue;//Check character again
					}
				}
			}
			else if (str[0] == '(') {
				s.push(str[0]);
			}
			else if (str[0] == ')') {
				char c;
				if (!s.empty())
					while ((c = s.top()) != '(') {
						postfix += c;
						if (!s.empty())
							s.pop();
					}
				if (!s.empty())
					s.pop();
			}
			getline(cin, str);
		}
		while (!s.empty()) {
			char c = s.top();
			s.pop();
			postfix += c;
		}
		if (ctr == 0) {
			cout << postfix << endl;
			ctr++;
		}
		else
			cout << endl << postfix << endl;
	}
	return 0;
}