(C++) How would I display a value rounded to the nearest integer?

[soul5]

Like for example

Prompting message reads.

"Please enter a positive value"

Example:

Please enter a positive value: 234.7
Rounded to the nearest integer the number is: 235


Please enter a positive value: 10.3
Rounded to the nearest integer the number is: 10


What I have

int num;

cout<< "Please enter a positive value";

cin>> num;

cout<< num << endl;




The problem is that doesn't round the number to the nearest interger so what would I do to round it?

 

[rootX]

Like for example

Prompting message reads.

"Please enter a positive value"

Example:

Please enter a positive value: 234.7
Rounded to the nearest integer the number is: 235


Please enter a positive value: 10.3
Rounded to the nearest integer the number is: 10


What I have

int num;

cout<< "Please enter a positive value";

cin>> num;

cout<< num << endl;




The problem is that doesn't round the number to the nearest interger so what would I do to round it?

(int) (3.5+0.5)

 

[soul5]

(int) (3.5+0.5)

Dude that's not it.

 

[CRGreathouse]

rootX gave a correct example of the calculation needed. You need to input as a float, not an int, then convert to an int by rounding as in rootX's suggestion.

 

[KTC]

It does help if num is a floating point variable, rather than an int.

Round to zero (truncation)

int rounded_num = static_cast<int>(num);

Round to +infinity

int rounded_num = std::floor(num + 0.5);

Round away from zero

int rounded_num = (num < 0.0)
    ? ((std::floor(num) == num - 0.5) ? std::floor(num) : std::floor(num + 0.5))
    : std::floor(num + 0.5);

Really shouldn't do direct == with floating points, but that's another subject.

Or in C++0x:

int rounded_num = std::round(num);

Round to even
Um, have fun...

 

[zyh]

It does help if num is a floating point variable, rather than an int.

Round to zero (truncation)

int rounded_num = static_cast<int>(num);

Round to +infinity

int rounded_num = std::floor(num + 0.5);

Round away from zero

int rounded_num = (num < 0.0)
    ? ((std::floor(num) == num - 0.5) ? std::floor(num) : std::floor(num + 0.5))
    : std::floor(num + 0.5);

Really shouldn't do direct == with floating points, but that's another subject.

Or in C++0x:

int rounded_num = std::round(num);

Round to even
Um, have fun...

very insteresting, but I think rootx's answer is enough and simple.