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digitalmars.D - Initializing Arrays

reply Joseph Bell <josephabell tx.rr.com> writes:
Hi.

I'm new to D but not new to programming.  I had a few questions 
regarding  arrays and their initialization:

// celsius.init will be 100, the boiling point of water
typedef float celsius = 100.00;

If I declare an array of type celsius to group the low, average, and 
high temperature:

celsius[3] temps;

I'd like to be able to default the elements to something other than the 
value of celsius.init:  a syntax like

celsius[3] temps = [0, 20, 18];

In the global namespace (outside of main) the gdc compiler doesn't have 
any issues with this and gives me what I expect, temps[0] = 0.0, 
temps[1] = 20.0, and temps[2] = 18.0.  Within main however I get errors 
such as:

arrayex.d:22: Error: cannot implicitly convert expression ([0,20,18]) of 
type int[3] to celsius.

Is there a way to uniquely specify the default value of each element of 
an array in this manner in a non-global namespace?

Many thanks for any insight.

Joe
Jan 21 2007
parent reply "Lionello Lunesu" <lionello lunesu.remove.com> writes:
Not sure if it'll work, but try using [cast(celcius)0,20,18].
Casting the first element will change the type of the array.

L.

"Joseph Bell" <josephabell tx.rr.com> wrote in message 
news:ep0h1h$18ph$1 digitaldaemon.com...
 Hi.

 I'm new to D but not new to programming.  I had a few questions regarding 
 arrays and their initialization:

 // celsius.init will be 100, the boiling point of water
 typedef float celsius = 100.00;

 If I declare an array of type celsius to group the low, average, and high 
 temperature:

 celsius[3] temps;

 I'd like to be able to default the elements to something other than the 
 value of celsius.init:  a syntax like

 celsius[3] temps = [0, 20, 18];

 In the global namespace (outside of main) the gdc compiler doesn't have 
 any issues with this and gives me what I expect, temps[0] = 0.0, temps[1] 
 = 20.0, and temps[2] = 18.0.  Within main however I get errors such as:

 arrayex.d:22: Error: cannot implicitly convert expression ([0,20,18]) of 
 type int[3] to celsius.

 Is there a way to uniquely specify the default value of each element of an 
 array in this manner in a non-global namespace?

 Many thanks for any insight.

 Joe 

Jan 21 2007
parent Joseph Bell <josephabell tx.rr.com> writes:
That does indeed work as expected.  The following also works:

celsius[3] temps = cast(celsius[3])[0, 20, 18];

and as I expect the following works okay as well:

int[3] ints = [1, 2, 3];

I find it curious though that

celsius[3] temps = [70,80,90]

compiles cleanly in the global namespace and not in the main function.

Any idea why?


Lionello Lunesu wrote:
 Not sure if it'll work, but try using [cast(celcius)0,20,18].
 Casting the first element will change the type of the array.

 
 L.
 
 "Joseph Bell" <josephabell tx.rr.com> wrote in message 
 news:ep0h1h$18ph$1 digitaldaemon.com...
 Hi.

 I'm new to D but not new to programming.  I had a few questions regarding 
 arrays and their initialization:

 // celsius.init will be 100, the boiling point of water
 typedef float celsius = 100.00;

 If I declare an array of type celsius to group the low, average, and high 
 temperature:

 celsius[3] temps;

 I'd like to be able to default the elements to something other than the 
 value of celsius.init:  a syntax like

 celsius[3] temps = [0, 20, 18];

 In the global namespace (outside of main) the gdc compiler doesn't have 
 any issues with this and gives me what I expect, temps[0] = 0.0, temps[1] 
 = 20.0, and temps[2] = 18.0.  Within main however I get errors such as:

 arrayex.d:22: Error: cannot implicitly convert expression ([0,20,18]) of 
 type int[3] to celsius.

 Is there a way to uniquely specify the default value of each element of an 
 array in this manner in a non-global namespace?

 Many thanks for any insight.

 Joe 


Jan 21 2007