Cod sursa(job #1813055)

Utilizator Remus12Remus Dan Remus12 Data 22 noiembrie 2016 17:54:38
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.06 kb
#include <iostream>
#include <fstream>
using namespace std;

const int N=1000001;
int p;
char s[N];

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

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]=='-'){
        p++;
        semn=-semn;
    }
    if(s[p]=='('){
        p++;
        val=expresie();
        p++;
        return semn*val;
    }
    while(s[p]>='0' && s[p]<='9'){
        val=val*10+(s[p]-'0');
        p++;
    }
    return semn*val;
}
int main()
{
    in.getline(s,N);
    out<<expresie()<<"\n";
    in.close();
    out.close();
    return 0;
}