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I don't understand how this phrase is computed in C #

I am testing this code

int value = (char)+(int)-(float)+(double)-1;

and I get this result (1) which means that the value 1

! How is this calculated?

EDIT:

Yesterday I had an interview with a company and that was their question and I didn’t know how this number was obtained 1

. So I am trying to understand how this result happens.

+3


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3 answers


It's really just a casting. The +

and signs -

are used only to negate a number. So, take the first bit of the expression, which differs -1

from double

:

(double)-1

Then take the result of this and draw it onto float

:



(float)+(-1)

And so on, until you are done with char

, which will implicitly be passed to int

.

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Challenges:

  • int value = (char)+(int)-(float)+(double)-1;

  • int value = (int)-(float)-1;

  • int value = 1;

Have the same intermediate language pushing number 1 onto the evaluation stack:



IL_0000:  nop         
IL_0001:  ldc.i4.1    // <-- push to stack
IL_0002:  stloc.0     // value
IL_0003:  ldloc.0     // value
IL_0004:  call        LINQPad.Extensions.Dump<Int32>
IL_0009:  pop         
IL_000A:  ret

Optimization reduces your operation to a simple set.

+5


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This is a matter of simple arithmetic:

(double)-1

calculated as -1

(float)+(double)-1

calculated as -1

(int)-(float)+(double)-1

calculated as +1

(char)+(int)-(float)+(double)-1

calculated as +1

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