Web在x64架构中，eax寄存器是rax寄存器的低32位，此处我们可以认为两者值相等，代码第一行是把判断条件（对应于C++代码中的a值）复制到eax寄存器中，第二行代码是把.L4段偏移rax寄存器值大小的地址赋值给rax寄存 … Web177. Use switch. In the worst case the compiler will generate the same code as a if-else chain, so you don't lose anything. If in doubt put the most common cases first into the switch statement. In the best case the optimizer may find a better way to generate the code. Common things a compiler does is to build a binary decision tree (saves ...
C++ Switch Statement: Advantages, Syntax, and Examples
WebWhen C++ reaches a break keyword, it breaks out of the switch block. This will stop the execution of more code and case testing inside the block. When a match is found, and the job is done, it's time for a break. There is no need for more testing. A break can save a lot of execution time because it "ignores" the execution of all the rest of the ... WebC、C++、Objective -C 等都属于编译型语言. 解释型语言. 在程序运行前将源程序预编译成中间语言，然后再由解释器执行中间语言. 每次执行解释型语言的程序都需要进行一次编译，因此解释型语言的程序运行效率通常较低，而且它不能脱离解释器独立运行。 sim teck siong
if快还是switch快？解密switch背后的秘密 - 知乎 - 知乎专栏
Webswitch 语句必须遵循下面的规则：. switch 语句中的 expression 必须是一个整型或枚举类型，或者是一个 class 类型，其中 class 有一个单一的转换函数将其转换为整型或枚举类型。; 在一个 switch 中可以有任意数量的 case 语句。每个 case 后跟一个要比较的值和一个冒号。 case 的 constant-expression 必须与 switch 中 ... WebMar 20, 2024 · Working of switch Statement in C++. The working of the switch statement in C is as follows: Step 1: The switch expression is evaluated. Step 2: The evaluated value is then matched against the present case values. Step 3A: If the matching case value is found, that case block is executed. Step 3B: If the matching code is not found, then the ... WebFeb 19, 2010 · Note that a switch with (n) case…break basic blocks can be translated into (n) basic blocks reachable from no more than log(n) branches, whereas a chain of if…else if takes up to (n) branches unless the compiler is very clever. OP noted that the switch is faster than the else if. @STing: Function calls are a class of branch instructions, period, … simtec powerband air hockey tabletop game