Cod sursa(job #1267257)

Utilizator delia_99Delia Draghici delia_99 Data 19 noiembrie 2014 18:15:11
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.12 kb
#include <cstdio>
using namespace std;
char s[100005],*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();
        }
        if(*p=='-')
        {
            ++p;
            r-=termen();
        }
    }
    return r;
}

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

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