Cod sursa(job #1829939)

Utilizator TherevengerkingSurani Adrian Therevengerking Data 15 decembrie 2016 21:04:16
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.14 kb
#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("evaluare.in");
ofstream fout("evaluare.out");
int i=0;
string s;
bool isDigit(char x);
int eval();
int termen();
int factor();
bool isDigit(char x)
{
    if(x>=48 && x<=57)return 1;
    return 0;
}
int eval()
{
    int r=termen();
    while(s[i]=='+' or s[i]=='-')
    {
        if(s[i]=='+')
        {
            ++i;
            r+=termen();
        }
        else
        {
            ++i;
            r-=termen();
        }
    }
    return r;
}
int termen()
{
    int r = factor();
    while(s[i]=='*' or s[i]=='/')
    {
        if(s[i]=='*')
        {
            ++i;
            r*=factor();
        }
        else
        {
            ++i;
            r/=factor();
        }
    }
    return r;
}
int factor()
{
    int r;
    if(s[i]=='(')
    {
        ++i;
        r=eval();
        ++i;
    }
    else
    {
        r=0;
        while(isDigit(s[i]))
        {
            r=r*10+s[i]-'0';
            ++i;
        }
    }
    return r;
}
int main()
{
    fin>>s;
    fout<<eval();
    return 0;
}