Cod sursa(job #1883887)

Utilizator Cioarec_GeorgeCioarec George Cioarec_George Data 18 februarie 2017 11:51:23
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.31 kb
#include <iostream>
#include <cstring>
#include <fstream>
#include <cstdlib>

using namespace std;

ifstream f("evaluare.in");
ofstream g("evaluare.out");

const int n=100001;
char c[n];
int p;

int expresie();
int termen();
int factor();

int expresie()
{
    int sum=termen();
    while(c[p]=='+' || c[p]=='-')
    {
        if(c[p]=='+')
        {
            ++p;
            sum+=termen();
        }
        else
        {
            ++p;
            sum-=termen();
        }
    }
    return sum;
}

int termen()
{
    int prod=factor();
    while(c[p]=='*' || c[p]=='/')
    {
        if(c[p]=='*')
        {
            ++p;
            prod*=factor();
        }
        else
        {
            ++p;
            int imp=factor();
            if(imp!=0)
                prod/=imp;
            else
            {
                cout<<"Nu se poate imparti la 0";
                exit(0);
            }
        }
    }
    return prod;
}

int factor()
{
    int val=0, semn=1;
    while(c[p]=='-')
    {
        ++p;
        semn=-semn;
    }
    if(c[p]=='(')
    {
        ++p;
        val=expresie();
        ++p;
        return semn*val;
    }
    while(c[p]>='0' && c[p]<='9')
    {
        val=val*10+(c[p]-'0');
        ++p;
    }
    return semn*val;
}

int main()
{
    f.getline(c, 100000);
    g<<expresie();
    return 0;
}