CODEWITHSUNDEEP
c#casting
user3127554
user3127554

Reputation: 577

Divide two decimals and cast result to int

I'm trying to cast the result of a divide result to an int in c#

This is my code: 

decimal testDecimal = 5.00; // testDecimal always is dividable by 0.25 with 0 rest
int times=0;

int times = testDecimal / Convert.ToDecimal(0.250); 

// error returned -> Cannot implicitly convert type 'decimal' to 'int'.

if I change my cast to

int times = (int) testDecimal / Convert.ToDecimal(0.250); 
//also returns an error: Cannot implicitly convert type 'decimal' to 'int'

How could I get the result (20) as an integer? What am I doing wrong?

Upvotes: 4

Views: 1658

Answers (8)

Flydog57
Flydog57

Reputation: 7111

I'm not sure why you have Convert.ToDecimal(0.250). Why convert the float (0.250) to a decimal at run time? Why not just use a decimal literal (like 0.25M)? As other folks have noted, you need to cast the results of the division to an int, like:

decimal testDecimal = 5M;
int times = (int) (testDecimal / 0.25M);
Assert.AreEqual(20, times);

Also, as other folks have noted, you may want to think through how you do your conversion from decimal to int. Do you want to the default behavior (what you get from a simple cast), or do you want round up, round down, round to even, etc.? In this case, since the division yields an integral result, it doesn't matter, but in the general case, you'll want to put some thought into it.

By the way, the reason you have an error in this code:

int times = (int) testDecimal / Convert.ToDecimal(0.250);

is that you are casting testDecimal (5.0M) to an int (5). Then you are dividing it by a decimal (0.25M), which yields a decimal (20.0M). Finally, you are trying to assign that decimal to an integer, and the compiler signals an error.

HTH

Upvotes: 0

Kyle B
Kyle B

Reputation: 2889

Wrap your expression in parenthesis so that you can convert it:

// int times = (int)testDecimal / 0.250m; 
int times = (int)(testDecimal / 0.250m);

Just a note, make sure you are try/catching while converting because not all decimal values can fit into int.

try
{
    times = (int)decimal.MaxValue;
}
catch(OverflowException ex)
{
    // Value was either too large or too small for an Int32.
}

Upvotes: 0

Erhode
Erhode

Reputation: 172

First of all you should add "M" suffix to your testDecimal declaration otherwise your 5.00 is a litteral and not a decimal.

decimal testDecimal = 5.00M;

Now, your compiler is not aware that your division result is an integer. Even if your devision can be casted to "int", for him, a decimal devided by another is a decimal and not an integer. You have to implicitly cast it:

int times = (int)(testDecimal / 0.250M);

Works like charm for me.

Upvotes: 0

Hossein Golshani
Hossein Golshani

Reputation: 1897

If you want a numeric literal to be treated as decimal, use the suffix m or M. By this way there is no need to use Convert.ToDecimal.

decimal testDecimal = 5.00M;
int times = (int)(testDecimal / 0.250M);

Upvotes: 0

Haytam
Haytam

Reputation: 4733

As everybody answered, you have to add parenthesis to cast the result of the your division instead of just trying to cast the first part and then getting the error after the division.

I also want to point out that it is not necessary to use Convert.ToDecimal just to declare your constant as adecimal, you could use C# suffixs to do so:

int times = (int)(testDecimal / 0.250m);

Upvotes: 3

Andrew Drake
Andrew Drake

Reputation: 665

Try this:

 times = (int)(testDecimal / Convert.ToDecimal(0.250));

Without the extra parenthesis, it is trying to convert ONLY testDecimal to integer, then trying to convert the int/decimal result to an integer implicitly, which is what causes the error.

In an unrelated note, you are trying to declare the variable 'times' twice.

Upvotes: 3

apomene
apomene

Reputation: 14389

You have to cast the whole division result. try like: 

int times = (int) (testDecimal / Convert.ToDecimal(0.250));

Be careful though because this could suffer the seemingly random floating point arithmetic error depending on which values you use. https://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html

You may avoid this by first rounding the value.

(int) Math.Round(testDecimal / Convert.ToDecimal(0.250));

Upvotes: 1

Steve
Steve

Reputation: 11963

first you don't need to do convert to decimal, you can just do 0.25m

and then you can do 

times = (int) (testDecimal / 0.25m);

do note that if the number is too big this might give you wrong result.

Upvotes: 0

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