字节数组转浮点数或整数(200分)

N

nslhw

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• 2008-01-28

• #1

有一个4字节的浮点数,按字节从高到低取出来存在字节数组中,如何将这个数组转换恢复成浮点数
(实际使用是delphi中使用串口访问控件,将数据读到字节数组中,需要恢复数据.)
如var SM:array of byte;
UA:single(real);
setlength(SM,4);
SM[0]:=$42;
SM[1]:=$9F;
SM[2]:=$E9;
SM[3]:=$7B;
UA:=??

 

L

liuchong

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• 2008-01-28

• #2

var
SM:array of Byte;
UA:Single;
PByte;
I:Byte;
begin
SetLength(SM,4);
SM[0]:=$42;
SM[1]:=$9F;
SM[2]:=$E9;
SM[3]:=$7B;
P:=@UA;
for I:=0 to 3do
begin
P^:=SM;
Inc(P);
end;
Caption:=FloatToStr(UA);
end;

 

L

liuchong

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• 2008-01-28

• #3

方法二：
var
SM:array of Byte;
UA:Single;
PSingle;
begin
SetLength(SM,4);
SM[0]:=$42;
SM[1]:=$9F;
SM[2]:=$E9;
SM[3]:=$7B;
P:=Pointer(SM);
UA:=P^;
Caption:=FloatToStr(UA);
end;

 

N

nslhw

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GUEST, unregistred user!

• 2008-01-28

• #4

接受答案了.

 

L

LSUPER

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GUEST, unregistred user!

• 2008-01-28

• #5

就一句话：
Move(PChar(SM)^, UA, SizeOf(Single));
套用上面的例子：
var
SM:array of Byte;
UA:Single;
begin
SetLength(SM,4);
SM[0]:=$42;
SM[1]:=$9F;
SM[2]:=$E9;
SM[3]:=$7B;
Move(PChar(SM)^, UA, SizeOf(Single));
Caption:=FloatToStr(UA);
end;