Cod sursa(job #2491289)

Utilizator Alexandra_GheAlexandra Gheorghe Alexandra_Ghe Data 12 noiembrie 2019 11:28:30
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.12 kb
#include <iostream>
#include <fstream>
#include <cstring>
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();
        }
        if(s[p]=='/')
        {
            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';
    }
    return semn*val;
}

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