Cod sursa(job #194414)

Utilizator wefgefAndrei Grigorean wefgef Data 10 iunie 2008 14:47:57
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.96 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;
	
	if (s[p] == '(') 
		++p, ret = Expresie(), ++p;
	else
		while (p < N && (s[p] >= '0' && s[p] <= '9'))
			ret = ret*10 + s[p++]-'0';
		
	return ret;
}

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

int Expresie() {
	int ret = Factor();
	
	while (p < N && (s[p] == '+' || s[p] == '-')) {
		int op = s[p++] == '+';
		
		int aux = Factor();
		
		if (op) ret += aux;
		else ret -= aux;
	}
	
	return ret;
}

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