求realround函数的实现代码
如题...
谢谢
问题点数：20、回复次数：6Top
1 楼dragonzll（）回复于 2006-03-04 20:27:09 得分 0
就是实数按小数位数四舍五入
realround(number,3)Top
2 楼zhangl_cn（和尚-修行）回复于 2006-03-04 23:01:36 得分 5
function RealRound(number:Double;Bit:integer):Double;
var
i,j:integer;
begin
j:=10;
for i:=1 to bit-1 do j:=j*10;
Result:=trunc(number*j+0.5)/j;
end;
Top
3 楼Delphi1985（Darkhorse）回复于 2006-03-05 09:31:43 得分 0
嗯,就是这样
按上面的算法Top
4 楼liangqingzhi（老之）回复于 2006-03-05 10:01:27 得分 5
Math单元的RoundTo函数Top
5 楼fairyhoodwater（fairyhood）回复于 2006-03-06 15:57:20 得分 5
别忘了在USE里加上Math，找上面的用就行Top
6 楼unsigned（僵哥(发站内消息，请附上链接或问题说明，否则不予回复)）回复于 2006-03-06 16:26:36 得分 5
uses
math;
function DRound(Value:double;cnt:byte):double;
var
fTmp:double;
nTmp:double;
k:int64;
begin
Result:=Value;
if cnt>18 then exit;
nTmp:=Power(10.0,cnt);
fTmp:=0.5;
fTmp:=fTmp/nTmp;
Result:=fTmp+Result;
Result:=Result*nTmp;
k:=0;
asm
fld qword ptr Result
//__ftol begin
push ebp
mov ebp,esp
LEA ESP,k
wait
fstcw word ptr [ebp-$04]
wait
mov al,[ebp-$03]
or [ebp-$04],$00000c01
fldcw word ptr [ebp-$04]
fistp qword ptr [ebp-$0c]
mov [ebp-$03],al
fldcw word ptr [ebp-$04]
mov eax ,[ebp-$0c]
mov edx,[ebp-$08]
mov esp,ebp
pop ebp
//__ftol end
push esp
lea esp,k
mov [esp],eax
add esp,4
mov [esp],edx
mov esp,ebp
pop esp
fild qword ptr k
fstp qword ptr Result
fld qword ptr nTmp
fdivr qword ptr Result
fstp qword ptr Result
end;
end;
function DRoundUp(Value:double;cnt:byte):double;
var
fTmp:double;
nTmp:double;
k:int64;
begin
Result:=Value;
if cnt>18 then exit;
nTmp:=Power(10.0,cnt);
fTmp:=1;
fTmp:=fTmp/nTmp;
Result:=Result*nTmp;
k:=0;
asm
fld qword ptr Result
//__ftol begin
push ebp
mov ebp,esp
LEA ESP,k
wait
fstcw word ptr [ebp-$04]
wait
mov al,[ebp-$03]
or [ebp-$04],$00000c01
fldcw word ptr [ebp-$04]
fistp qword ptr [ebp-$0c]
mov [ebp-$03],al
fldcw word ptr [ebp-$04]
mov eax ,[ebp-$0c]
mov edx,[ebp-$08]
mov esp,ebp
pop ebp
//__ftol end
push esp
lea esp,k
mov [esp],eax
add esp,4
mov [esp],edx
mov esp,ebp
pop esp
fild qword ptr k
fstp qword ptr Result
fld qword ptr nTmp
fdivr qword ptr Result
fstp qword ptr Result
end;
if Result<Value then Result:=Result+fTmp;
end;
function DRoundDown(Value:double;cnt:byte):double;
var
fTmp:double;
nTmp:double;
k:int64;
begin
Result:=Value;
if cnt>18 then exit;
nTmp:=Power(10.0,cnt);
Result:=Result*nTmp;
k:=0;
asm
fld qword ptr Result
//__ftol begin
push ebp
mov ebp,esp
LEA ESP,k
wait
fstcw word ptr [ebp-$04]
wait
mov al,[ebp-$03]
or [ebp-$04],$00000c01
fldcw word ptr [ebp-$04]
fistp qword ptr [ebp-$0c]
mov [ebp-$03],al
fldcw word ptr [ebp-$04]
mov eax ,[ebp-$0c]
mov edx,[ebp-$08]
mov esp,ebp
pop ebp
//__ftol end
push esp
lea esp,k
mov [esp],eax
add esp,4
mov [esp],edx
mov esp,ebp
pop esp
fild qword ptr k
fstp qword ptr Result
fld qword ptr nTmp
fdivr qword ptr Result
fstp qword ptr Result
end;
end;Top
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