Cod sursa(job #1129165)

Utilizator DenisacheDenis Ehorovici Denisache Data 27 februarie 2014 20:30:56
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.04 kb
#include <fstream>
#include <cstring>
using namespace std;
ifstream f("evaluare.in");
ofstream g("evaluare.out");
char v[100005],*p=v;
long termen();
long factor();
long eval()
{
    long r=termen();
    while (*p=='+' || *p=='-')
    {
        if (*p=='+')
        {
            ++p;
            r+=termen();
        }
        else if (*p=='-')
        {
            ++p;
            r-=termen();
        }
    }
    return r;
}
long termen()
{
    long r=factor();
    while (*p=='*' || *p=='/')
    {
        if (*p=='*')
        {
            ++p;
            r*=factor();
        }
        else
        {
            ++p;
            r/=factor();
        }
    }
    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.getline(v,100005);
    g<<eval();
    return 0;
}