Cod sursa(job #2676563)

Utilizator DragosC1Dragos DragosC1 Data 24 noiembrie 2020 16:40:24
Problema Evaluarea unei expresii Scor 60
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.18 kb
#include <fstream>
#include <cstring>
#include <cctype>
using namespace std;

char e[100001];
int n, i;

int evalExpresie();
int evalTermen();
int evalFactor();
int formareNumar();

int main() {
    ifstream f("evaluare.in");
    f.getline(e, 100001);
    f.close();
    n = strlen(e);
    ofstream g("evaluare.out");
    g << evalExpresie();
    g.close();
    return 0;
}

int evalFactor() {
    int p;
    if (e[i] == '(') {
        i++;
        p = evalExpresie();
        i++;
    }
    else 
        p = formareNumar();
    return p;
}

int evalTermen() {
    int q = evalFactor();
    while (i < n && (e[i] == '*' || e[i] == '/')) {
        i++;
        if (e[i - 1] == '*')
            q *= evalTermen();
        else q /= evalTermen();
    }
    return q;
}

int evalExpresie() {
    int t = evalTermen();
    while (i < n && (e[i] == '+' || e[i] == '-')) {
        i++;
        if (e[i - 1] == '+')
            t += evalTermen();
        else t -= evalTermen();
    }
    return t;
}

int formareNumar() {
    int nr = 0;
    while (isdigit(e[i]) && i < n) {
        nr = nr * 10 + e[i] - '0';
        i++;
    }
    return nr;
}