Cod sursa(job #1123990)

Utilizator andreismara97Smarandoiu Andrei andreismara97 Data 26 februarie 2014 10:50:59
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.29 kb
#include<cstdio>

using namespace std;

const int N = 100001;

char s[N];
int p;

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

int expresie()
{
    int sum = termen();
    while (s[p] == '+' || s[p] == '-')
    {
        if (s[p] == '+')
        {
            p++; //trec peste +
            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++; // trec peste (
        val = expresie();
        p++; // trec peste )
        return semn * val;
    }
    while (s[p] >= '0' && s[p] <= '9')
    {
        val = val * 10 + s[p] - '0';
        p++;
    }
    return semn * val;
}

int main()
{
    freopen("evaluare.in","r",stdin);
    freopen("evaluare.out","w",stdout);

    scanf("%s",s);

    printf("%d\n", expresie());
    return 0;
}