floating point literal

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内联汇编
 
浮点文字定义了编译时间常数，其值在源文件中指定.
Original:
Floating point literal defines a compile-time constant whose value is specified in the source file.
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[编辑] 语法

浮点文字有两种语法。第一个由以下几部分组成：1
Original:
A floating-point literals have two syntaxes. The first one consists of the following parts:
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  • 非空序列包含小数点的字符定义了显著的小数位数
    Original:
    nonempty sequence of decimal digits containing a decimal point character (defines significant)
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  • （可选的）e或E可选的负号或加号和非空的十进制数字序列（DEFINES指数）
    Original:
    （可选的） e or E followed with optional minus or plus sign and nonempty sequence of decimal digits (defines exponent)
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  • （可选的）后缀类型说明符作为一个l，f，L或F
    Original:
    （可选的） a suffix type specifier as a l, f, L or F
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第二个由以下几部分组成：1
Original:
The second one consists of the following parts:
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  • 非空序列的小数位数（定义见显著）
    Original:
    nonempty sequence of decimal digits (defines significant)
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  • e或E可选的负号或加号和非空的十进制数字序列（DEFINES指数）
    Original:
    e or E followed with optional minus or plus sign and nonempty sequence of decimal digits (defines exponent)
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  • （可选的）后缀类型说明符作为一个l，f，L或F
    Original:
    （可选的） a suffix type specifier as a l, f, L or F
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后缀类型说明符定义浮点文字的实际类型
Original:
The suffix type specifier defines the actual type of the floating-point literal:
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  • （没有后缀）定义double
    Original:
    (no suffix) defines double
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  • f F定义float
    Original:
    f F defines float
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  • l L定义long double
    Original:
    l L defines long double
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[编辑] 解释

一个十进制科学记数法，这意味着指数为功率10的显著multiplied.
的的
Original:
A decimal scientific notation is used, meaning that the exponent is the power of 10 by which the significant is multiplied.
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在数学上的意义123e4是“123×10 4 </ SUP>”
Original:
The mathematical meaning of 123e4 is 123×104
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</div>

[编辑] 为例

std::cout << 123.456e-67 << '\n'
          << .1E4f       << '\n'
          << 58.         << '\n'
          << 4e2         << '\n';

Output: 

1.23456e-65
1000
58
400
来自“http://zh.cppreference.com/mwiki/index.php?title=cpp/language/floating_literal&oldid=28861”