首先對於一維數組,如:數組
char a[]={1,2,3,4};
int b[]={1,2,3,4,5};
float c[]={1.0,2.0,3.0};
如何求取這些數組的長度呢?能夠使用sizeof(),但因爲sizeof()返回的是字節長度,因此能夠使用sizeof(x)/sizeof((x)[0])。.net
#include "stdio.h"
#include "stdlib.h"
#define ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0]))blog
void main(void)
{
char a[] = { 1,2,3,4 };
int b[] = { 1,2,3,4,5 };
float c[] = { 1.0,2.0,3.0 };io
int length_a = 0;
int length_b = 0;
int length_c = 0;class
length_a = ARRAY_SIZE(a);
length_b = ARRAY_SIZE(b);
length_c = ARRAY_SIZE(c);原理
printf("length of a[]=%d\n", length_a);
printf("length of b[]=%d\n", length_b);
printf("length of c[]=%d\n", length_c);float
system("pause");
}
運行結果以下:
那麼對於二維數組呢?
如:im
char a[][2] = { 1,2,3,4 };
int b[][3] = { 1,2,3,4,5,6 };
float c[][2] = { 1.0,2.0,3.0,4.0 };
能夠使用sizeof(x)/sizeof((x)[0][0])。總結
#include "stdio.h"
#include "stdlib.h"
#define ARRAY_SIZE_2(x) (sizeof(x)/sizeof((x)[0][0]))二維數組
void main(void)
{
char a[][2] = { 1,2,3,4 };
int b[][3] = { 1,2,3,4,5,6 };
float c[][2] = { 1.0,2.0,3.0,4.0 };
int length_a = 0;
int length_b = 0;
int length_c = 0;
length_a = ARRAY_SIZE_2(a);
length_b = ARRAY_SIZE_2(b);
length_c = ARRAY_SIZE_2(c);
printf("length of a[]=%d\n", length_a);
printf("length of b[]=%d\n", length_b);
printf("length of c[]=%d\n", length_c);
system("pause");
}
運行結果以下:
總結:原理就是利用sizeof(),先求取數組元素所佔的總的字節長度,再求出一個首元素所佔的字節長度(即元素類型的長度),相除便可獲得數組的長度。--------------------- 做者:weixin_37536484 來源:CSDN 原文:https://blog.csdn.net/weixin_37536484/article/details/78686028 版權聲明:本文爲博主原創文章,轉載請附上博文連接!