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selenaqd
September 29th, 2012, 05:40 PM
Hi guys,

when I compile the follow c++ code with dev, it gave me right answer but with code blocks, it always said NAN. I have been using code blocks for a while, so I am quite get use to it, donot really want to change. do you have any idea why this is happening?

p.s. I also tried with other two computers to compile with code blocks, it showed the same result.
Thanks advance!

Selena

//#include "..\std_lib_facilities.h"

const char let = 'L';
const char quit = 'Q';
const char print = ';';
const char number = '8';//t is a number token
const char name = 'a';
//----------------------------------------------------------------------
struct Token {
char kind;
double value;
string name;
Token(char ch) :kind(ch),name(""),value(0) { cout << "Token: '" << ch << "'" << endl; }
Token(char ch, double val) :kind(ch),name(""),value(val) { cout << "Token: '" << ch << ",' value: " << val << endl; }
Token(char ch, string n) :kind(ch),name(n),value(0) { cout << "Token: '" << ch << ",' name: '" << n << "'" << endl; }
};
//----------------------------------------------------------------------------------
class Token_stream {
public:
//construct
Token_stream() :full(0), buffer(0) { }
Token get();
void unget(Token t) { buffer=t; full=true; }
void ignore(char);
private:
bool full;
Token buffer;
};
//---------------------------------------------------------------------------------------


Token Token_stream::get()
{
if (full) {
full=false;
return buffer;
}

char ch;
cin >> ch;

switch (ch) {
case '(':
case ')':
case '+':
case '-':
case '*':
case '/':
case '%':
case ';':
case '=':
return Token(ch);
case '.':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
{
cin.unget();
double val;
cin >> val;
return Token(number,val);
}
default:
if (isalpha(ch)) {
string s;
s += ch;
while(cin.get(ch) && (isalpha(ch) || isdigit(ch)))
s+=ch;
cin.unget();
if (s == "let") return Token(let);
if (s == "quit") return Token(quit);
return Token(name,s);
}
error("Bad token");
}
}
//----------------------------------------------------------------------------
void Token_stream::ignore(char c)
{
if (full && c==buffer.kind) {
full = false;
return;
}
full = false;

char ch;
while (cin>>ch)
if (ch==c) return;
}
//-------------------------------------------------------------------------
struct Variable {
string name;
double value;
Variable(string n, double v) :name(n), value(v) { }
};
//------------------------------------------------------------------------
vector<Variable> names;


//----------------------------------------------------------------------
double get_value(string s)
{
for (int i = 0; i< (int) names.size(); ++i)
if (names[i].name == s) return names[i].value;
error("get: undefined name ",s);
}

//---------------------------------------------------------------------
void set_value(string s, double d)
{
for (int i = 0; i<= (int) names.size(); ++i)
if (names[i].name == s) {
names[i].value = d;
return;
}
error("set: undefined name ",s);
}
//----------------------------------------------------------------------------------
bool is_declared(string s)
{
for (int i = 0; i<(int)names.size(); ++i)
if (names[i].name == s) return true;
return false;
}
//--------------------------------------------------------------------------------
Token_stream ts;
//-------------------------------------------------------------------------
double expression();
//----------------------------
double primary()
{
Token t = ts.get();
switch (t.kind) {
case '(':
{
double d = expression();
t = ts.get();
if (t.kind != ')')
error("'(' expected");
return d;
}
case '-':
return - primary();
case number:
{
cout << "Primary: number: " << t.value << endl;
return t.value;
}
case name:
return get_value(t.name);
default:
error("primary expected");
}
}
//--------------------------------------------------------
double term()
{
double left = primary();

while(true) {
Token t = ts.get();
switch(t.kind) {
case '*':
left *= primary();
break;
case '/':
{ double d = primary();
if (d == 0) error("divide by zero");
left /= d;
break;
}
default:
ts.unget(t);
return left;
}
}
}
//-----------------------------------------------------------
double expression()
{
double left = term();
while(true) {
Token t = ts.get();
switch(t.kind) {
case '+':
left += term();
break;
case '-':
left -= term();
break;
default:
ts.unget(t);
return left;
}
}
}
//-------------------------------------------------
double declaration()
{
Token t = ts.get();
if (t.kind != 'a') error ("name expected in declaration");
string name = t.name;
if (is_declared(name)) error(name, " declared twice");
Token t2 = ts.get();
if (t2.kind != '=') error("= missing in declaration of " ,name);
double d = expression();
names.push_back(Variable(name,d));
return d;
}
//-------------------------------------------------------------------------
double statement()
{
Token t = ts.get();
switch(t.kind) {
case let:
return declaration();
default:
ts.unget(t);
return expression();
}
}
//-------------------------------------------------------------------
void clean_up_mess()
{
ts.ignore(print);
}

//----------------------------------------------------------
const string prompt = "> ";
const string result = "= ";
//-----------------------------------------------------
void calculate()
{
while(true) try {
cout << prompt;
Token t = ts.get();
while (t.kind == print) t=ts.get();
if (t.kind == quit) return;
ts.unget(t);
cout << result << statement() << endl;
}
catch(runtime_error& e) {
cerr << e.what() << endl;
clean_up_mess();
}
}
//-------------------------------------------------

int _tmain(int argc, _TCHAR* argv[])
{
try {
cout << "Calculator is online." << endl;
calculate();
keep_window_open();
return 0;
}
catch (exception& e) {
cerr << "exception: " << e.what() << endl;
char c;
while (cin >>c&& c!=';') ;
return 1;
}
catch (...) {
cerr << "exception\n";
char c;
while (cin>>c && c!=';');
return 2;
}
}

cogier
September 29th, 2012, 07:47 PM
Err! You posted this in Absolutely Beginner Talk?!!

MG&TL
September 29th, 2012, 08:17 PM
Hi guys,

when I compile the follow c++ code with dev, it gave me right answer but with code blocks, it always said NAN. I have been using code blocks for a while, so I am quite get use to it, donot really want to change. do you have any idea why this is happening?


The reason for this is likely that Code::Blocks uses a different compiler, compiler version, or default compiler flags than Dev-C++ (I am assuming by 'dev' you mean Dev-C++).

I'm not about to read through your code (please re-post in [CODE] tags, then I may re-consider :) ), but I do note you're using Bjarne Stroustrup's C++ guide (std_lib_facilities.h). I learned using this, it's a great guide. Good choice!

Have patience, and you'll get there.

Old_Grey_Wolf
September 29th, 2012, 08:28 PM
Moved to Packaging and Compiling Programs.