我可以在for循环的初始化中声明不同类型的变量吗?
为什么这个C ++代码不能在VS2010下编译:
Why does this C++ code not compile under VS2010:
for ( int a = 0, short b = 0; a < 10; ++a, ++b ) {}
p>
while this one does:
short b = 0;
for ( int a = 0; a < 10; ++a, ++b ) {}
是否禁止在循环初始化中的不同类型的两个变量的声明?
Is the declaration of two variables of different types inside the for-loop initializer prohibited? If so, how can you work around it?
是的,这是禁止的。正如在其他方面你不能在一个声明语句中声明不同类型的变量( edit :modulo @MrLister提到的声明器修饰符)。您可以为(struct {int a = 0; short b = 0;} d; da
Yes, that is prohibited. Just as otherwise you cannot declare variables of differing types in one declaration statement (edit: modulo the declarator modifiers that @MrLister mentions). You can declare structs
for (struct { int a = 0; short b = 0; } d; d.a < 10; ++d.a, ++d.b ) {}
C ++ 03代码:
C++03 code:
for (struct { int a; short b; } d = { 0, 0 }; d.a < 10; ++d.a, ++d.b ) {}
当然,当 0
,您可以完全省略初始值设置,并写 = {}
。
Of course when all are 0
, you can omit the initializers altogether and write = { }
.