Cod sursa(job #1606283)

Utilizator BratuAlexandruBratu Alexandru Razvan BratuAlexandru Data 20 februarie 2016 08:48:21
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.11 kb
#include <fstream>

using namespace std;

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

int p;
char s[100001];

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

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

int termen()
{
    int prod=factor();
    while(s[p]=='*'||s[p]=='/')
    {
        if(s[p]=='*')
        {
            p++;
            prod*=factor();
        }
        if(s[p]=='/')
        {
            p++;
            prod/=factor();
        }
    }
    return prod;
}

int factor()
{
    int val=0,semn=1;
    while(s[p]=='-')
    {
        semn=-semn;
        p++;
    }
    if(s[p]=='(')
    {
        p++;
        val=expresie();
        p++;
        return semn*val;
    }
    while(s[p]>='0'&&s[p]<='9')
    {
        val=val*10+(s[p]-'0');
        p++;
    }
    return semn*val;
}
int main()
{
    in.getline(s, 100001);
    in.close();
    out << expresie() << "\n";
    out.close();
    return 0;
}