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1.字符串的定义:
(1)单个字符:
char ch='i';//单个字符的定义
(2)一维字符串数组:
char arr[]="love";(这种方法定义的一维字符串数组必须赋值) char arr[4];(想内存申请创建可以存储3个字符的数组空间) char
arr[5]=”love”;(开辟5个字节的空间存放字符love,最后一个字节存放'\0'字符) char
arr[5]={'l','o',v','e'};(开辟5个字节的空间存放字符love,最后一个字节存放'\0'字符)
2.字符串长度
(1)sizeof(arr)是求该字符串的有多少字符,由于\0也是一个字符,所以数组实际长度加一;
(2)strlen(arr)因为strlen碰见\0就会停止,所以结果是数组的实际长度
3.字符串和字符数组的区别:
由于C语言中没有string关键字,所以不能定义字符串,只能用字符数组来表示字符串,也因此很多人认为两者是一个概念,笔者以前也是这样认为的,后来听到老师提过字符串和字符数组是有区别,因此我开始翻阅一些书籍,才了解了
两者的区别,接下来请听我说:
(1)字符数组:
是定义一个字符数组,向内存申请的空间是数组里存放元素个数,向内存存放数组的字符元素
char arr1[] = { 'l','o','v','e' };
(2)字符串:
是定义一个字符数组,向内存申请的空间是数组里存放元素个数+1,向内存存放数组的字符元素+'\0',编译时编译器会自动在字符串的末尾添加此值,字符串是一个
只读型字符型数组,不能够通过指针更改字符串内部数据
char arr2[] = "love";
可以简单的这么说:c语言的字符串由C的字符数组末尾加上'\0'变形而成。
#include<stdio.h> int main(void) { char arr1[] = { 'l','o','v','e' }; char
arr2[] = "love"; printf("arr1的长度 :%zu\n", sizeof(arr1)); printf("arr2的长度
:%zu\n", sizeof(arr2)); printf("arr1的长度 :%d\n", strlen(arr1)); printf("arr2的长度
:%d\n", strlen(arr2)); printf("arr1的内容 :%s\n",arr1); printf("arr2的长度 :%s\n",
arr2); return 0; }
注:第三行出现:arr1的长度 :36和第五行出现:arr1的内容 :love烫烫烫烫烫烫烫烫烫烫烫烫烫烫love的原因是
strlen和printf函数均是遇到'\0'才停住
,由于定义字符数组时没有加上'\0'导致'\0'位置未知,故出现此种情况,用我以前的一篇博客(初识C语言(1))做的图供大家理解: