Please comment on my integer to string code.

[manoj1978]

Hi All,
I wrote the following to print an integer in its string
representation for base -36 to 36.
Please comment on this code.

#include <iostream>
#include <string>

using std::abs;
using std::cout;
using std::endl;
using std::reverse;
using std::string;

char charTable[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

void printBase(int i, int base)
{
if ((abs(base) <= 1) || (abs(base) > 36) || (i == 0))
{
cout << "0" << endl;
return;
}

string str = "";
if ((base > 0) && (i < 0))
{
str += "-";
i = -i;
}

do {
if (i % base >= 0)
{
str += charTable[i % base];
i = i / base;
} else {
str += charTable[i % base - base];
i = i /base + 1;
}
} while(i);
reverse(str.begin(), str.end());
cout << str << endl;
}

int main()
{
for(int i = -55; i <= 55; i++)
{
cout << i << " = ";
printBase(i,-10);
}
}

Thanks and Regards,
manoj.

[Dietmar Kuehl]

ma*******@gmail.com wrote:

A quick search of comp.lang.c shows that what you say is true for C90
also.but differs in C99.

I know that this was addressed in C99 and it is likely to work in
C++, too. However, this does not really help if you want to have
your code portable.
--
<mailto:di***********@yahoo.com> <http://www.dietmar-kuehl.de/>
<http://www.eai-systems.com> - Efficient Artificial Intelligence

[manoj1978]

Dietmar Kuehl wrote:

ma*******@gmail.com wrote:

A quick search of comp.lang.c shows that what you say is true for C90
also.but differs in C99.

I know that this was addressed in C99 and it is likely to work in
C++, too. However, this does not really help if you want to have
your code portable.

Yes.Especially since I dont work with that many C99 compilers also.
I have taken care of that now.
Regards,
manoj

[BobR]

ma*******@gmail.com wrote in message ...

BobR wrote:

// ------------------------------------
class Manoj{ [snip]
}; //class Manoj
// ------------------------------------
int main(){
Manoj Man;
Man.execute( 10, std::cout);
Man.execute( 16 );

ofstream File("MyTest.txt");
if( !File ){
std::cerr<<"ofstream File FAILURE!!"<<std::endl;
return EXIT_FAILURE;
}
for(int i( -36 ); i <= 36; ++i){ Man.execute( i, File );} // for(i)
return 0;
} // main()end
// ------------------------------------
--
Bob R
POVrookie
Hi Bob,
Thank you very much for the code.
I changed ofstream File("MyTest.txt"); to std::ofstream
File("MyTest.txt");

Oooops. It was very late and I got in a hurry to get it posted. Glad you
figured it out.
Changed charTable into character array and added step to handle
INT_MIN.
It works fine.Once again thanks.
Regards,
manoj.

I didn't know if you knew 'class', but, thought it would be easier to test
that way (and I wouldn't have to transfer/translate code from the form I test
in ( that class is inside another class of same design, in my 'testbench'
wxWidgets program)).

So, is it *all* working to your satisfaction now?

--
Bob R
POVrookie

[manoj1978]

BobR wrote:

ma*******@gmail.com wrote in message ...
Oooops. It was very late and I got in a hurry to get it posted. Glad you
figured it out. No probs :-)
I didn't know if you knew 'class', but, thought it would be easier to test
that way (and I wouldn't have to transfer/translate code from the form I test
in ( that class is inside another class of same design, in my 'testbench'
wxWidgets program)). Yeah,I know class.Not used in the code,since i initially wrote this in
c.I just modified it so as to post here :-)
So, is it *all* working to your satisfaction now?

Yes.I thought it may need much work to handle % and / truncating to
infinity.
But on testing with the following functions,found that code needed
change only in INT_MAX handler,since "if (i % base >= 0)" take care of
this change automatically.

int divToInf(int a,int b)
{
bool sign = true;
int add = 0;
if (a < 0)
{
a = -a;
sign = !sign;
add = 1;
}
if (b <0)
{
b = -b;
sign = !sign;
}

if (sign)
{
return a/b + add;
} else {
return -( a/b + add);
}
}

int modToInf(int a,int b)
{
return a - b * divToInf(a,b);
}

Once again thanks.
Regards,
manoj.

[Richard Herring]

In message <11**********************@p10g2000cwp.googlegroups .com>,
ma*******@gmail.com writes

Hi All,
I wrote the following to print an integer in its string
representation for base -36 to 36.
Please comment on this code.

#include <iostream>
#include <string>

using std::abs;
using std::cout;
using std::endl;
using std::reverse;
using std::string;

char charTable[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

void printBase(int i, int base)
{
if ((abs(base) <= 1) || (abs(base) > 36) || (i == 0))
{
cout << "0" << endl;
return;
}

[snip rest of code]

You've had lots of feedback on the other stuff, but I haven't noticed
anybody commenting on this combination of two completely unrelated
tests:

If the argument is zero, output "0". Fine; that's the expected result.

If the base is out of bounds, output "0". Do you really want an input
error to produce the same result as valid data?

(Incidentally, what have you got against base-1 representation? ;-)

--
Richard Herring

[manoj1978]

Richard Herring wrote:
I havent seen this post due to google's interface.Sorry about the
delay.

You've had lots of feedback on the other stuff, but I haven't noticed
anybody commenting on this combination of two completely unrelated
tests:

If the argument is zero, output "0". Fine; that's the expected result.

If the base is out of bounds, output "0". Do you really want an input
error to produce the same result as valid data?
I got that comment also :-)
I have seperated them.
(Incidentally, what have you got against base-1 representation? ;-) Nothing.Somebody asked about negative base numbers in a group.I
searched in math forum about it and wrote the code.
--
Richard Herring

Regards,
manoj.

[Richard Herring]

In message <11**********************@u72g2000cwu.googlegroups .com>,
ma*******@gmail.com writes

Richard Herring wrote:
I havent seen this post due to google's interface.Sorry about the
delay.

You've had lots of feedback on the other stuff, but I haven't noticed
anybody commenting on this combination of two completely unrelated
tests:

If the argument is zero, output "0". Fine; that's the expected result.

If the base is out of bounds, output "0". Do you really want an input
error to produce the same result as valid data?

I got that comment also :-)
I have seperated them.

(Incidentally, what have you got against base-1 representation? ;-)

Nothing.Somebody asked about negative base numbers in a group.I
searched in math forum about it and wrote the code.

Base *1*, not general non-negative bases. It's very easy: 1, 11, 111,
1111, 11111, ...

--
Richard Herring

[manoj1978]

Richard Herring wrote:

Base *1*, not general non-negative bases. It's very easy: 1, 11, 111,
1111, 11111, ...

:-)

[Ben Pope]

Richard Herring wrote:

Base *1*, not general non-negative bases. It's very easy: 1, 11, 111,
1111, 11111, ...

Looks like a classic off by one bug to me!

Surely it's:
0, 00, 000, 0000, ...

At least, in a C++ newsgroup.

Ben Pope
--
I'm not just a number. To many, I'm known as a string...