Cod sursa(job #152527)

Utilizator kiss_meDumitru Maria-Cristina kiss_me Data 9 martie 2008 15:24:06
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.79 kb
#include <cstdio>
#include <cstring>

char s[100010];
char *p=s;
char operand[4][4] = {"+-", "*/", "^", ""};
const long hmax = 2;

long operatie(long x, long y, char c) {
	switch ( c ) {
		case '+': return x+y;
		case '-': return x-y;
		case '*': return x*y;
		case '/': return x/y;
	}
	return 0;
}

long eval(long);

long element() {
	long r=0;
	if ( *p == '(' ) {
		++p; r = eval(0); ++p;
	} else {
		while ( strchr("0123456789", *p) )
			r = r*10 + *(++p-1) - '0';
	}
	return r;
}

long eval(long h) {
	long r = (h==hmax)?element():eval(h+1);
	while ( strchr(operand[h], *p) ) 
		r = operatie(r, eval(h+1), *(++p-1));
	return r;
}


int main() {
	fgets(s, 100010, fopen("evaluare.in", "r"));
	fprintf(fopen("evaluare.out", "w"), "%ld\n", eval(0));
	return 0;
}