Cod sursa(job #2352157)

Utilizator aurelionutAurel Popa aurelionut Data 23 februarie 2019 00:44:43
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.95 kb
#include <fstream>
#include <cstring>

using namespace std;

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

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

int main()
{

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