Cod sursa(job #3250746)

Utilizator alexdraguAlexandru Dragu alexdragu Data 23 octombrie 2024 15:48:42
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.11 kb
#include <bits/stdc++.h>

using namespace std;
ifstream fin("evaluare.in");
ofstream fout("evaluare.out");
char s[100005];
int i;
int expresie();
int termen();
int factor();
int constanta();
int main()
{
    fin>>s;
    i=0;
    fout<<expresie();
    return 0;
}

int expresie()
{
    int r=termen();
    while(s[i]=='+' || s[i]=='-')
    {
        if(s[i]=='+')
        {
            i++;
            r+=termen();
        }
        else
        {
            i++;
            r-=termen();
        }
    }
    return r;
}

int termen()
{
    int r=factor();
    while(s[i]=='*'||s[i]=='/')
    {
        if(s[i]=='*')
        {
            i++;
            r*=factor();
        }
        else
        {
            i++;
            r/=factor();
        }
    }
    return r;
}

int factor()
{
    int r=0;
    if(s[i]=='(')
    {
        i++;
        r=expresie();
        i++;
    }
    else r=constanta();
    return r;
}

int constanta()
{
    int r=0;
    while(s[i]>='0'&&s[i]<='9')
    {
        r=r*10+s[i]-'0';
        i++;
    }
    return r;
}