Question

在目标C中,我宣布这样一阵列:

int length = 10;
int a[length];

This does not cause any errors in Xcode but other compliers like Visual Studio. Please tell me how it works. Should I use it or use malloc/calloc instead?

Answer 1

Variable length arrays were introduced in C99. Microsoft s current compiler (VC2010) doesn t support C99 (or at least the VLA part of it) as far as I m aware.

http://www.un.org/Depts/DGACM/index_chinese.htm

类似:

int length = 10;
int *a = malloc (length * sizeof(int));
if (a == NULL) {
    doSomethingIntelligentSinceNoMemoryLeft();
} else {
    useToHeartsContent (a[0], "thru", a[9]);
    free (a);
}

或许也可以使用<代码>alloca <>>>> >,该编码与甚低价竞标相类似,因为它将空间分配给变量记忆区。

但是,您必须到。虽然alloca使你自动停职,但停职通常比 Smalloc heap小,如果你耗尽了他的成绩,则让你回到NUL。如果你冲破你,这很可能表明自己是坠毁。

alloca(n) is probably acceptable for small enough values of n.

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