Cod sursa(job #2377408)

Utilizator urweakurweak urweak Data 10 martie 2019 10:58:08
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.22 kb
#include <fstream>
#include <cstring>
using namespace std;
ifstream in("evaluare.in");
ofstream out("evaluare.out");
const int NMax = 100001;
char x[NMax], *p = x;

long termen();
long factor();

long eval()
{
    long r = termen();
    while(*p == '+' || *p == '-')
    {
        switch(*p)
        {
            case '+':
                ++p;
                r+=termen();
                break;
            case '-':
                ++p;
                r-=termen();
                break;

        }
    }
    return r;
}

long termen()
{
    long r = factor();
    while(*p =='*' || *p =='/')
    {
        switch(*p)
        {
            case '*':
                ++p;
                r*=factor();
                break;
            case '/':
                ++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()
{
    in >> x;
    out << eval();
    return 0;
}