+= , -= , *= , /=
Description描述
Perform a mathematical operation on a variable with another constant or variable. The += (et al) operators are just a convenient shorthand for the expanded syntax, listed below.
对一个变量和另一个参数或变量完成一个数学运算。+=（以及其他）可以缩短语法长度。
Syntax语法
x += y; // equivalent to the expression x = x + y; // 等价于 x = x + y;
x -= y; // equivalent to the expression x = x - y; // 等价于 x = x - y;
x *= y; // equivalent to the expression x = x * y; // 等价于 x = x * y;
x /= y; // equivalent to the expression x = x / y; // 等价于 x = x / y;
Parameters参数
x: any variable type
x：任何变量类型
y: any variable type or constant
y：任何变量类型或常数
Examples范例
x = 2;
x += 4; // x now contains 6 // x现在为6
x -= 3; // x now contains 3 // x现在为3
x *= 10; // x now contains 30 // x现在为30
x /= 2; // x now contains 15 // x现在为15
Syntax语法
x++; // increment x by one and returns the old value of x
// 将x的值加1并返回原来的x的值。 ++x; // increment x by one and returns the new value of x // 将x的值加1并返回现在的x的值。
x-- ; // decrement x by one and returns the old value of x // 将x的值减1并返回原来的x的值。
--x ; // decrement x by one and returns the new value of x // 将x的值减1并返回现在的x的值。
Parameters参数
x: an integer or long (possibly unsigned)
x：一个整数或长整数（可以无符号）
Returns返回
The original or newly incremented / decremented value of the variable.
返回变量原始值或增加/消耗后的新值。
Examples范例
x = 2;
y = ++x; // x now contains 3, y contains 3 // x现在为3，y为3
y = x--; // x contains 2 again, y still contains 3 // x现在仍然为2，y将为3