Cod sursa(job #167573)

Utilizator toni2007Pripoae Teodor Anton toni2007 Data 29 martie 2008 19:54:13
Problema Evaluarea unei expresii Scor 100
Compilator c Status done
Runda Arhiva educationala Marime 1.07 kb
#include <stdio.h>
#define MAX 100005
char S[MAX], *p=S;
int termen();
int factor();
int eval() {
	int r = termen();
	while ( *p=='+' || *p=='-' ) {
		switch ( *p ) {
			case '+':
				++p;						// trecem peste semnul "+"
				r += termen(); 
				break;
			case '-':
				++p;						// trecem peste semnul "-"
				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 == '(' ) {						// avem o subexpresie
        ++p;								// trecem peste '('
		r = eval(); 
		++p;								// trecem peste ')'
    } else {  
        while ( *p>='0' && *p<='9' )  {		// avem un numar
            r = r*10 + *p - '0';  
			++p;
		}
    }  
    return r;
}

int main() { 
    freopen("evaluare.in","r",stdin);
    freopen("evaluare.out","w",stdout);
    gets(S);
    printf("%d",eval());
    return 0;
}