Cod sursa(job #2677688)

Utilizator RaresCelescuRares Celescu RaresCelescu Data 27 noiembrie 2020 10:42:43
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.19 kb
#include <iostream>
#include <fstream>

using namespace std;

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

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++;
            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('0'<=s[p]&&s[p]<='9')
    {
        val=val*10+(s[p]-'0');
        p++;
    }
    return semn*val;
}

int main()
{
    in>>s;
    out<<expresie();
    return 0;
}