Cod sursa(job #2676658)

Utilizator Alex_DiaconuDiaconu Alexandru Alex_Diaconu Data 24 noiembrie 2020 18:59:26
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.17 kb
#include <fstream>
#include <string>

using namespace std;

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

string s;
int p;

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();
        }
        else
        {
            p++;
            prod/=factor();
        }
    }
    return prod;
}

int factor()
{
    int val=0, semn=1;
    while (s[p]=='-')
    {
        p++;
        semn=-semn;
    }
    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()
{
    cin >> s;
    cout << expresie();
    return 0;
}