Cod sursa(job #1676884)

Utilizator danstefanDamian Dan Stefan danstefan Data 6 aprilie 2016 11:04:57
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.07 kb
#include <fstream>
#include <cstdio>
#include <cstring>
using namespace std;
int i;
char st[100010],*p;
int eval();
int termen();
int factor();
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=0;
    if(*p=='(')
        {
            ++p;
            r=eval();
            ++p;
        }
        else
        while(*p>='0'&&*p<='9'){
            r*=10;
            r+=(int)*p-'0';
            ++p;
        }
    return r;
}
int main()
{
    freopen("evaluare.in","r",stdin);
    ofstream g ("evaluare.out");
    gets(st);
    p=st;
    int n=eval();
    g<<n;
    return 0;}