Re: Flummoxed - Please Help!
On 2/18/2014 4:06 PM, Mike Copeland wrote:
In article <le0eu5$gnl$1@dont-email.me>, v.bazarov@comcast.invalid
says...
I have the following (rather simple, I think) code which compiles but
executes in a bizarre way: the code in the subprogram is skipped when
called. 8<{{
Here's the code and the call to it I use:
Please advise... TIA
The logic error is on the line 42 of your original program, at least
according to my crystal ball, which is the best source of information I
have at this point, since you've chosen not to post the entire program.
http://www.parashift.com/c++-faq/posting-code.html
Fair enough; I was sloppy. Here's the entire program code:
// CPP10 Test Bed Program MRCopeland 02/18/2014
#include "stdafx.h"
string spellNumber(double value)
{
int ii, dPos, nn;
char wc;
string digits;
ostringstream ossw;
static string builder;
ossw.str(""); // Convert integer portion of value to string
ossw << value;
digits = ossw.str();
dPos = digits.find('.');
if(dPos != string::npos) digits.erase(dPos);
nn = digits.length(); // Traverse characters in reverse order
wc = digits.back();
for(ii = digits.length()-1; ii >= 0; ii--)
{
int ndigit = (int)(digits[ii]-'0');
int column = (digits.length()-(ii+1));
} // for
return builder;
}
int main(int argc, char *argv[])
{
string str = spellNumber(123.45);
return EXIT_SUCCESS;
} // main
During execution, the following occurs during the IDE trace:
1. The subprogram is entered and immediately jumps to the "return
builder" statement. (Why?)
2. Then, the function is reentered and code steps are taken - until the
"if" statement executes. The logic works as expected with the data
presented ("digits" is runcated to "123"), whereupon the function exits
(!).
3. The statements beyond the "if" are skipped for no apparent reason.
Any thoughts?
I took your code and made only one change:
//#include "stdafx.h"
#include <string>
#include <sstream>
using std::string;
using std::ostringstream;
(since I have no idea what was in your 'stdafx.h' header). The program
compiled and ran fine (under the debugger). Stepping through it showed
that it followed all statements and returned an empty string (since no
change is made to 'builder' object in the 'spellNumber' function).
It sounds that you're trying to debug an optimized version of your
program (a "release" version). Perhaps you should disable optimizations
in order to step through it. The optimizer is often not the best tool
for verifying the logic of your program because it can determine and
throw away the code that has no effect. For instance, all the code that
follows the 'if' statement has no side effect (no change is made to any
memory location that would be noticed by the caller of the function),
methinks.
V
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