Cod sursa(job #1246589)

Utilizator codi22FMI Condrea Florin codi22 Data 21 octombrie 2014 12:44:41
Problema Evaluarea unei expresii Scor 10
Compilator cpp Status done
Runda Arhiva educationala Marime 1.06 kb

#include <iostream>
#include <fstream>
#include <cstdio>
using namespace std;
char S[1000100],*p=S;
ifstream f("evaluare.in");
ofstream g("evaluare.out");
long termen();
long factor();
long eval();
long eval()
{
    long r=termen();
    while (*p=='+'||*p=='-')
    {
        if (*p=='+')
        {
            ++p;
            r+=termen();
            break;
        }
        else
        {
            ++p;
            r-=termen();
            break;
        }
    }
    return r;
}
long termen()
{
    long r=factor();
    while (*p=='*'||*p=='/')
    {
        if (*p=='*')
        {
            ++p;
            r*=factor();
            break;
        }
        else
        {
            ++p;
            r/=factor();
            break;
        }
    }
    return r;
}
long factor()
{
    long r=0;
    if (*p=='(')
    {
        ++p;
        r=eval();
        ++p;
    }
    else while (*p>='0'&&*p<='9')
    {
        r=r*10+*p-'0';
        ++p;
    }
    return r;
}
int main()
{
    f>>S;
    g<<eval();
}