Infinite loop

[aakashjohari]

I have written a program -

#include <iostream>

using namespace std;

int main()
{
float D;

D=0.1;

while ( 1.0-D != 0.0 ) {
cout << D << endl;
D=D+0.1;
}

return 0;
}

On executing, while loop becomes an infinite loop. The answer that i got is, there is the problem with precision. But if i use this condition in if statement that it returns correctly true or false.

[Bazzy]

Try to modify the condition in ( int(10-D*10) != 0 )

[aakashjohari]

My question is why it is an infinite loop.

[Bazzy]

Because the float is wrong for a little value
instead of getting 0 (from 1.0-D) you will get something like -1.19209e-7 (this is what I get)

(Same problem as in http://www.cplusplus.com/forum/general/4920/ )

[exception]

http://www.cplusplus.com/forum/articles/3827/
(I'm starting to wonder if anyone here even bothers to look for a solution before posting)

[jsmith]

Very good article. Personally I think we need an article that suggests to solve problems in the integer domain if at all possible and resort to floating point only if absolutely unavoidable.

[aakashjohari]

Ok Bazzy! but why it works correctly with if statement....

[exception]

Very good article

Thanks ;-)

Personally I think we need an article that suggests to solve problems in the integer domain if at all possible

I doubt that it would be of much use - I wonder why I wrote that other article in the first place. Those who could use it don't seem to be willing to read it, as seen from the post above...