在不重写变量的情况下乘以变量

var x = 5;
var y = 10;
x *= y; // 等同于 x = x * y;
console.log(x); // 输出50

x = 5
y = 10
x *= y  # 等同于 x = x * y
print(x)  # 输出50

int x = 5;
int y = 10;
x *= y; // 等同于 x = x * y;
System.out.println(x); // 输出50