Cod sursa(job #1600592)

Utilizator danstefanDamian Dan Stefan danstefan Data 15 februarie 2016 10:51:28
Problema Evaluarea unei expresii Scor 10
Compilator cpp Status done
Runda Arhiva educationala Marime 0.88 kb
#include <fstream>
#include <cstdio>
#include <cstring>
using namespace std;
char s[100010],*p;
long long n;
int eval();
int termen();
int factor();
int eval()
{
	int r;
	r=termen();
	while(*p=='+'||*p=='-')
	if(*p=='+')
		{
			++p;
			r+=termen();
			break;
		}
		else
	if(*p=='-')
		{
			++p;
			r-=termen();
			break;
		}
	return r;
}
int termen()
{
	int r;
	r=factor();
	while(*p=='*'||*p=='/')
	if(*p=='*')
		{
			++p;
			r*=factor();
			break;
		}
		else
	if(*p=='/')
		{
			++p;
			r/=factor();
			break;
		}
	return r;
}
int factor()
{
	int r;
	r=0;
	if(*p=='(')
	{
		++p;
		r=eval();
		++p;
	}
	else
	{
		while('0'<=*p && *p<='9')
		{
			r*=10;
			r+=(int)*p-'0';
			++p;
		}
	}
	return r;
}

int main()
{
	freopen("evaluare.in","r",stdin);
	ofstream g ("evaluare.out");
	gets(s);
	p=s;
    n=eval();
	g<<n<<'\n';
}