Cod sursa(job #2675131)

Utilizator Cosmin2004_InfoMoldoveanu Cosmin Cosmin2004_Info Data 21 noiembrie 2020 10:23:23
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.25 kb
#include <cstdio>
#include <cstring>

using namespace std;
const int NMAX = 100005;
char s[NMAX];
char *p = s;
int termen();
int factor();
int eval() {
    int r = termen();
    while(*p == '+' || *p == '-') {
        switch(*p) {
            case '+':
                ++p;
                r += termen();
            break;
            case '-':
                ++p;
                r -= termen();
            break;
        }
    }
    return r;
}
int termen() {
    int r = factor();
    while(*p == '*' || *p == '/') {
        switch(*p) {
            case '*':
                ++p;
                r *= factor();
            break;
            case '/':
                ++p;
                r /= factor();
            break;
        }
    }
    return r;
}
int factor() {
    int r = 0;
    if(*p == '(') {
        ++p;
        r = eval();
        ++p;
    } else {
        while((*p ^ '0') < 10) {
            r = r * 10 + *p - '0';
            ++p;
        }
    }
    return r;
}

int main()
{
    freopen("evaluare.in", "r", stdin);
    freopen("evaluare.out", "w", stdout);
    int k = -1;
    char ch;
    while(scanf("%c", &ch) != -1 && ch != '\n') s[++k] = ch;
    printf("%d\n", eval());
    return 0;
}