又来了？ var a:real; b:double; 都可以啊！ 为什么一定要抱着Float不放呢？ delphi中没有Float啊！
A real type defines a set of numbers that can be represented with floating-point notation. The table below gives the ranges and storage formats for the fundamental real types.Type Range Significant digits Size in bytes Real48 2.9 x 10^?9 .. 1.7 x 10^38 11?2 6 Single 1.5 x 10^?5 .. 3.4 x 10^38 7? 4 Double 5.0 x 10^?24 .. 1.7 x 10^308 15?6 8 Extended 3.6 x 10^?951 .. 1.1 x 10^4932 19?0 10 Comp ?^63+1 .. 2^63 ? 19?0 8 Currency ?22337203685477.5808.. 922337203685477.5807 19?0 8 The generic type Real, in its current implementation, is equivalent to Double.Type Range Significant digits Size in bytes Real 5.0 x 10^?24 .. 1.7 x 10^308 15?6 8 Note: The six-byte Real48 type was called Real in earlier versions of Object Pascal. If you are recompiling code that uses the older, six-byte Real type, you may want to change it to Real48. You can also use the {$REALCOMPATIBILITY ON} compiler directive to turn Real back into the six-byte type.The following res apply to fundamental real types.Real48 is maintained for backward compatibility. Since its storage format is not native to the Intel CPU family, it results in slower performance than other floating-point types. Extended offers greater precision than other real types but is less portable. Be careful using Extended if you are creating data files to share across platforms. The Comp (computational) type is native to the Intel CPU and represents a 64-bit integer. It is classified as a real, however, because it does not behave like an ordinal type. (For example, you cannot increment or decrement a Comp value.) Comp is maintained for backward compatibility only. Use the Int64 type for better performance.Currency is a fixed-point data type that minimizes rounding errors in monetary calculations. It is stored as a scaled 64-bit integer with the four least-significant digits implicitly representing decimal places. When mixed with other real types in assignments and expressions, Currency values are automatically divided or multiplied by 10000.
var
a:real;
b:double;
都可以啊！
为什么一定要抱着Float不放呢？
delphi中没有Float啊！
Real48 2.9 x 10^?9 .. 1.7 x 10^38 11?2 6
Single 1.5 x 10^?5 .. 3.4 x 10^38 7? 4
Double 5.0 x 10^?24 .. 1.7 x 10^308 15?6 8
Extended 3.6 x 10^?951 .. 1.1 x 10^4932 19?0 10
Comp ?^63+1 .. 2^63 ? 19?0 8
Currency ?22337203685477.5808.. 922337203685477.5807 19?0 8
The generic type Real, in its current implementation, is equivalent to Double.Type Range Significant digits Size in bytes
Real 5.0 x 10^?24 .. 1.7 x 10^308 15?6 8
Note: The six-byte Real48 type was called Real in earlier versions of Object Pascal. If you are recompiling code that uses the older, six-byte Real type, you may want to change it to Real48. You can also use the {$REALCOMPATIBILITY ON} compiler directive to turn Real back into the six-byte type.The following res apply to fundamental real types.Real48 is maintained for backward compatibility. Since its storage format is not native to the Intel CPU family, it results in slower performance than other floating-point types.
Extended offers greater precision than other real types but is less portable. Be careful using Extended if you are creating data files to share across platforms.
The Comp (computational) type is native to the Intel CPU and represents a 64-bit integer. It is classified as a real, however, because it does not behave like an ordinal type. (For example, you cannot increment or decrement a Comp value.) Comp is maintained for backward compatibility only. Use the Int64 type for better performance.Currency is a fixed-point data type that minimizes rounding errors in monetary calculations. It is stored as a scaled 64-bit integer with the four least-significant digits implicitly representing decimal places. When mixed with other real types in assignments and expressions, Currency values are automatically divided or multiplied by 10000.