当代码流是这样的:
if(check())
{
...
...
if(check())
{
...
...
if(check())
{
...
...
}
}
}
我通常看到这种方法可以避免上述混乱的代码流:
do {
if(!check()) break;
...
...
if(!check()) break;
...
...
if(!check()) break;
...
...
} while(0);
有什么更好的方法可以避免这种工作/黑客，从而使其成为更高级别(行业级别)的代码?
任何跳出盒子的建议都是欢迎的!
当前回答
也许就像这样
#define EVER ;;
for(EVER)
{
if(!check()) break;
}
或者使用异常
try
{
for(;;)
if(!check()) throw 1;
}
catch()
{
}
使用异常还可以传递数据。
其他回答
为什么标记法没有被回答，这是自古以来使用的方法。
//you can use something like this (pseudocode)
long var = 0;
if(condition) flag a bit in var
if(condition) flag another bit in var
if(condition) flag another bit in var
............
if(var == certain number) {
Do the required task
}
类似于dasblinkenlight的答案，但避免了if语句中的赋值，这可能会被代码评审员“修复”:
bool goOn = check0();
if (goOn) {
...
goOn = check1();
}
if (goOn) {
...
goOn = check2();
}
if (goOn) {
...
}
...
当一个步骤的结果需要在下一步之前检查时，我使用这种模式，这与所有检查都可以在前面用一个大if(check1() && check2()…类型的模式。
如何移动if语句到一个额外的函数，产生一个数值或enum结果?
int ConditionCode (void) {
if (condition1)
return 1;
if (condition2)
return 2;
...
return 0;
}
void MyFunc (void) {
switch (ConditionCode ()) {
case 1:
...
break;
case 2:
...
break;
...
default:
...
break;
}
}
也许就像这样
#define EVER ;;
for(EVER)
{
if(!check()) break;
}
或者使用异常
try
{
for(;;)
if(!check()) throw 1;
}
catch()
{
}
使用异常还可以传递数据。
Try to extract the code into a separate function (or perhaps more than one). Then return from the function if the check fails. If it's too tightly coupled with the surrounding code to do that, and you can't find a way to reduce the coupling, look at the code after this block. Presumably, it cleans up some resources used by the function. Try to manage these resources using an RAII object; then replace each dodgy break with return (or throw, if that's more appropriate) and let the object's destructor clean up for you. If the program flow is (necessarily) so squiggly that you really need a goto, then use that rather than giving it a weird disguise. If you have coding rules that blindly forbid goto, and you really can't simplify the program flow, then you'll probably have to disguise it with your do hack.
