Cod sursa(job #2379591)

Utilizator sansRotaru Razvan Andrei sans Data 13 martie 2019 20:42:54
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.9 kb
#include <cstdio>

const long MAX = 100010;
char S[MAX], *p=S;

long termen();
long factor();


long eval() {
	long r = termen();
	while ( *p=='+' || *p=='-' ) {
		switch ( *p ) {
			case '+':
				++p;
				r += termen();
				break;
			case '-':
				++p;
				r -= termen();
				break;
		}
	}
	return r;
}

long termen() {
	long r = factor();
	while ( *p=='*' || *p=='/' ) {
		switch ( *p ) {
			case '*' :
				++p;
				r *= factor();
				break;
			case '/':
				++p;
				r /= factor();
				break;
		}
	}
	return r;
}


long factor() {
    long r=0;
    if ( *p == '(' ) {
        ++p;
		r = eval();
		++p;
    } else {
        while ( *p>='0' && *p<='9' )  {
            r = r*10 + *p - '0';
			++p;
		}
    }
    return r;
}

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