Cod sursa(job #194411)

Utilizator wefgefAndrei Grigorean wefgef Data 10 iunie 2008 14:37:17
Problema Evaluarea unei expresii Scor 40
Compilator cpp Status done
Runda Arhiva educationala Marime 0.86 kb
#include <cstdio>
#include <cstring>

const char FILEIN[] = "evaluare.in";
const char FILEOUT[] = "evaluare.out";
const int MAXN = 100005;

int N;
char s[MAXN];
int p;

int Expresie();

int Numar() {
	int ret = 0;
	while (p < N && (s[p] >= '0' && s[p] <= '9'))
		ret = ret*10 + s[p++]-'0';
	return ret;
}

int Factor() {
	int ret;
	
	if (s[p] == '(') ++p, ret = Expresie(), ++p;
	else ret = Numar();
	
	if (p < N && s[p] == '*')
		++p, ret *= Factor();
	if (p < N && s[p] == '/')
		++p, ret /= Factor();
	
	return ret;
}

int Expresie() {
	int ret = Factor();
	
	if (p < N && s[p] == '+')
		++p, ret += Expresie();
	if (p < N && s[p] == '-')
		++p, ret -= Expresie();
	
	return ret;
}

int main() {
	freopen(FILEIN, "r", stdin);
	freopen(FILEOUT, "w", stdout);
	
	scanf("%s", s);
	N = strlen(s);
	
	printf("%d\n", Expresie());
}