Cod sursa(job #2571248)

Utilizator BogdanFarcasBogdan Farcas BogdanFarcas Data 4 martie 2020 21:53:58
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.17 kb
#include <fstream>

using namespace std;

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

const int N=100003;
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]=='-')
    {
        semn=-semn;
        p++;
    }
    if(s[p]=='(')
    {
        p++;
        val=expresie();
        p++;
        return val*semn;
    }
    while(s[p]>='0'&&s[p]<='9')
    {
        val=val*10+s[p]-48;
        p++;
    }
    return val*semn;
}

int main()
{
    fin.getline(s,100001);
    fout<<expresie();
    return 0;
}