Cod sursa(job #3210306)

Utilizator Ionut2212Nedelcu Alexandru Ionut Ionut2212 Data 5 martie 2024 21:40:59
Problema Evaluarea unei expresii Scor 40
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.2 kb
#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;
ifstream fin ("evaluare.in");
ofstream fout ("evaluare.out");
char s[100001], i = 0;
int expresie();
int termen();
int factor();
int constanta();
int main()
{
    fin >> s;
    fout << expresie();
    return 0;
}
int expresie()
{
    int r = factor();
    while(s[i] == '-' || s[i] == '+')
    {
        if(s[i] == '+')
        {
            i++;
            r += factor();
        }
        else
        {
            i++;
            r -= factor();
        }
    }
    return r;
}
int factor()
{
    int r = termen();
    while(s[i] == '*' || s[i] == '/')
    {
        if(s[i] == '*')
        {
            i++;
            r *= termen();
        }
        else
        {
            i++;
            r /= termen();
        }
    }
    return r;
}
int termen()
{
    int r;
    if(s[i] == '(')
    {
        i++;
        r = expresie();
        i++;
    }
    else
        {
        r = constanta();
        }
    return r;
}
int constanta()
{
    int r = 0;
    while(isdigit(s[i]) == 1)
    {
        r = r * 10 + s[i] - '0';
        i++;
    }
    return r;
}