IDA Pro表达式（Expressions）

 　In the IDC expressions you can use almost all C operations except:

 complex assignment operations as'+='

 Constants are defined more or less like in C,with some minor differences.

 There are four type conversion operations:

 long(expr)floating point numbers are truncated during conversion

 char(expr)

 float(expr)

 __int64(expr)

 However,explicit type conversions are rarely required because all type conversions are made automatically:

 -addition:

 if both operands are strings,

 string addition is performed(strings are concatenated);

 if both operands are objects,

 object combination is performed(a new object is created)

 if floating point operand exists,

 both operands are converted to floats;

 otherwise

 both operands are converted to longs;

 -subtraction/multiplication/division:

 if floating point operand exists,

 both operands are converted to floats;

 if both operands are objects and the operation is subtraction,

 object subtraction is performed(a new object is created)

 otherwise

 both operands are converted to longs;

 -comparisons(==,!=,etc):

 if both operands are strings,string comparison is performed;

 if floating point operand exists,

 both operands are converted to floats;

 otherwise

 both operands are converted to numbers;

 -all other operations:

 operand(s)are converted to longs;

 If any of the long operands is 64bit,the other operand is converted to 64bit too.

 There is one notable exception concerning type conversions:if one operand is a string and the other is zero(0),then a string operation is performed.Zero is converted to an empty string in this case.

 The&operator is used to take a reference to a variable.References themselves cannot be modified once created.Any assignment to them will modify the target variable.For example:

 auto x,r;

 r=&x;

 r=1;//x is equal to 1 now

 References to references are immediately resolved:

 auto x,r1,r2;

 r1=&x;

 r2=&r1;//r2 points to x

 Since all non-object arguments are passed to functions by value,references are a good way to pass arguments by reference.

 中文翻译如下：

 在IDC表达式中，你可以使用几乎所有C操作，除了：

 复杂赋值运算符如'+='

 常量的定义类似于C，有一些微小的差异。

 有四种类型转换操作：

 long(expr)：浮点数在转换时会被截断。

 char(expr)

 float(expr)

 __int64(expr)

 然而，很少需要显式类型转换，因为所有类型转换都是自动进行的：

 加法：

 如果两个操作数都是字符串，则执行字符串连接操作。

 如果两个操作数都是对象，则执行对象组合操作（创建一个新对象）。

 如果存在浮点数操作数，则将两个操作数转换为浮点数。

 否则，将两个操作数转换为long类型。

 减法/乘法/除法：

 如果存在浮点数操作数，则将两个操作数转换为浮点数。

 如果两个操作数都是对象且操作是减法，则执行对象减法操作（创建一个新对象）。

 否则，将两个操作数转换为long类型。

 比较（==，！=，等）：

 如果两个操作数都是字符串，则执行字符串比较操作。

 如果存在浮点数操作数，则将两个操作数转换为浮点数。

 否则，将两个操作数转换为数字。

 所有其他操作：

 操作数将被转换为long类型。

 如果任何一个long操作数是64位的，那么另一个操作数也会被转换为64位。

 关于类型转换有一个值得注意的例外：如果一个操作数是字符串，另一个操作数是零（0），则会执行字符串操作。在这种情况下，零被转换为空字符串。

 &运算符用于获取变量的引用。一旦创建了引用，引用本身就无法修改。对它们的任何赋值都将修改目标变量。例如：

 auto x,r;

 r=&x;

 r=1;//现在x等于1

 引用引用会立即解析：

 auto x,r1,r2;

 r1=&x;

 r2=&r1;//r2指向x

 由于所有非对象参数都是按值传递给函数的，引用是通过引用传递参数的好方法。