Cod sursa(job #2068579)

Utilizator asavu16Andrei Savu asavu16 Data 18 noiembrie 2017 09:26:07
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.07 kb
#include <fstream>
#include <cstring>
using namespace std;
ifstream f("evaluare.in");
ofstream g("evaluare.out");
int val;
char s[100004],*p;
int eval();
int termen();
int factor();

int main()
{
    f.getline(s,100003);
    p=s;
    g<<eval();
    return 0;
}

int eval()
{
    int r;
    r=termen();
    while(*p=='+'||*p=='-')
    {
        if(*p=='+')
        {
            ++p;
            r+=termen();
        }
        else
        {
            ++p;
            r-=termen();
        }
    }
    return r;
}

int termen()
{
    int r;
    r=factor();
    while(*p=='*'||*p=='/')
    {
        if(*p=='*')
        {
            ++p;
            r*=factor();
        }
        else
        {
            ++p;
            r/=factor();
        }
    }
    return r;
}

int factor()
{
    int r;
    r=0;
    if(*p=='(')
    {
        ++p;
        r=eval();
        ++p;
    }
    else
    {
        while(*p>='0'&&*p<='9')
        {
            r=r*10+(int)*p-'0';
            ++p;
        }
    }
    return r;
}