Cod sursa(job #1090968)

Utilizator rzvrzvNicolescu Razvan rzvrzv Data 23 ianuarie 2014 13:08:14
Problema Evaluarea unei expresii Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 1.17 kb
#include<cstdio>
#include<cstring>

using namespace std;

char s[100014],*p;
int n;

int eval();

int termen();

int factor();

int main()
{
    freopen("evaluare.in","r",stdin);
    freopen("evaluare.out","w",stdout);
    gets(s);
    p=s;
    n=eval();
    printf("%d\n",n);
    return 0;
}

int eval()
{
    int r;
    r=termen();
    while(*p=='+'||*p=='-')
    {
        if (*p=='+')
        {
            ++p;
            r+=termen();
            break;
        }
        else
        {
            ++p;
            r-=termen();
            break;
        }
    }
    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*=10;
            r+=(int)*p-'0';
            ++p;
        }
    }
    return r;
}