Cod sursa(job #2413194)

Utilizator aurelionutAurel Popa aurelionut Data 23 aprilie 2019 01:56:48
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.91 kb
#include <fstream>
#include <cstring>

using namespace std;

const int NMAX = 100005;
int n, p;
char s[NMAX];
int expr(), termen(), factor();

int expr()
{
	int x = termen();
	while (p <= n && (s[p] == '+' || s[p] == '-'))
	{
		++p;
		if (s[p - 1] == '+')
			x += termen();
		else
			x -= termen();
	}
	return x;
}

int termen()
{
	int x = factor();
	while (p <= n && (s[p] == '*' || s[p] == '/'))
	{
		++p;
		if (s[p - 1] == '*')
			x *= factor();
		else
			x /= factor();
	}
	return x;
}

int factor()
{
	int x = 0;
	if (s[p] == '(')
	{
		++p;
		x = expr();
		++p;
	}
	else
	{
		while (p <= n && ('0' <= s[p] && s[p] <= '9'))
			x = x * 10 + (s[p++] - '0');
	}
	return x;
}

int main()
{
	ifstream fin("evaluare.in");
	ofstream fout("evaluare.out");
	fin >> (s + 1);
	n = strlen(s + 1);
	p = 1;
	fout << expr() << "\n";
	fin.close();
	fout.close();
	return 0;
}