+= , -= , *= , /=
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.
對一個變量和另一個參數(shù)或變量完成一個數(shù)學運算。+=（以及其他）可以縮短語法長度。
Syntax語法
x += y; // equivalent to the expression x = x + y; // 等價于 x = x + y;
x -= y; // equivalent to the expression x = x - y; // 等價于 x = x - y;
x *= y; // equivalent to the expression x = x * y; // 等價于 x = x * y;
x /= y; // equivalent to the expression x = x / y; // 等價于 x = x / y;
Parameters參數(shù)
x: any variable type
x：任何變量類型
y: any variable type or constant
y：任何變量類型或常數(shù)
Examples范例
x = 2;
x += 4; // x now contains 6 // x現(xiàn)在為6
x -= 3; // x now contains 3 // x現(xiàn)在為3
x *= 10; // x now contains 30 // x現(xiàn)在為30
x /= 2; // x now contains 15 // x現(xiàn)在為15
Syntax語法
x++; // increment x by one and returns the old value of x
// 將x的值加1并返回原來的x的值。 ++x; // increment x by one and returns the new value of x // 將x的值加1并返回現(xiàn)在的x的值。
x-- ; // decrement x by one and returns the old value of x // 將x的值減1并返回原來的x的值。
--x ; // decrement x by one and returns the new value of x // 將x的值減1并返回現(xiàn)在的x的值。
Parameters參數(shù)
x: an integer or long (possibly unsigned)
x：一個整數(shù)或長整數(shù)（可以無符號）
Returns返回
The original or newly incremented / decremented value of the variable.
返回變量原始值或增加/消耗后的新值。
Examples范例
x = 2;
y = ++x; // x now contains 3, y contains 3 // x現(xiàn)在為3，y為3
y = x--; // x contains 2 again, y still contains 3 // x現(xiàn)在仍然為2，y將為3