Cod sursa(job #790260)
#include <fstream>
using namespace std;
ifstream f("evaluare.in");
ofstream g("evaluare.out");
int l,i;
char s[100001];
int eval();
int termen();
int factor();
int eval()
{
int r=termen();
while (s[i]=='+' || s[i]=='-')
{
if (s[i]=='+')
{
i++;
r=r+termen();
}
if (s[i]=='-')
{
i++;
r=r-termen();
}
}
return r;
}
int termen()
{
int r=factor();
while (s[i]=='*' || s[i]=='/')
{
if (s[i]=='*')
{
i++;
r *= factor();
}
if (s[i]=='/')
{
i++;
r /= factor();
}
}
return r;
}
int factor()
{
int r=0;
if (s[i]=='(') { i++; //Trec peste '('
r=eval();
i++; // Trec peste ')'
}
else
while (s[i]>='0' && s[i]<='9')
{
r=r*10+(s[i]-'0');
i++;
}
return r;
}
int main()
{
f.getline(s,100001);
g<<eval();
f.close(); g.close();
return 0;
}