Cod sursa(job #2071895)

Utilizator GeorgeCalinPetruta George-Calin GeorgeCalin Data 21 noiembrie 2017 09:45:24
Problema Evaluarea unei expresii Scor 40
Compilator cpp Status done
Runda Arhiva educationala Marime 0.85 kb
#include <fstream>
#include <cstring>
#define nmax 100002
using namespace std;
ifstream fin("evaluare.in");
ofstream fout("evaluare.out");

char s[nmax],*p=s;
char leve[4][4]={"+-","*/","^",""};

int oper(int a,int b,char s)
{
    switch( s ) {
        case '+' :return a+b;
        case '-' :return a-b;
        case '*' :return a*b;
        case '/' :return a/b;
    }
}

int expr(int lev)
{
    int x,y;
    if(lev==2)
    {
        if(*p=='(')
        {
            ++p,x=expr(0),++p;
        }
        else
        {
            for(x=0 ;*p>='0'&&*p<='9';p++)
                x=x*10+*p-'0';
        }
    }
    else
    {
        for(x=expr(lev+1); strchr(leve[lev],*p); x=y)
            y=oper(x,expr(lev+1),*p++);
    }
    return x;
}

int main()
{
    fin.getline(s,nmax-1);
    fout<<expr(0);
    return 0;
}