如何找到物品的长度/数present一个数组? [英] How do I find the length/number of items present for an array?
问题描述
可能重复:结果
在功能参数数组的长度
我的数组大小为5。例如:
My array size is 5. For example:
arrCustId[5]
我怎么能知道有多少客户ID已经被present在我的阵列?
总之如何找到数组长度?
How can I know how many Customer IDs are already present in my array? In short how to find length of array?
推荐答案
如果数组是静态分配,使用的sizeof(阵列)/的sizeof(数组[0])
If the array is statically allocated, use sizeof(array) / sizeof(array[0])
如果它是动态分配的,但是,不幸的是你的运气,因为这一招总是返回的sizeof(POINTER_TYPE)/ sizeof的(数组[0])
(其中将有4个32位系统用char * S上),你可以或者a)保持的#define(或常量)不变,但或b)保持变量。
If it's dynamically allocated, though, unfortunately you're out of luck as this trick will always return sizeof(pointer_type)/sizeof(array[0])
(which will be 4 on a 32 bit system with char*s) You could either a) keep a #define (or const) constant, or b) keep a variable, however.
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