字符数组定义形式

#include <iostream>
using namespace std;

int main() {
    /*
     sizeof(x) 计算变量字节大小
     strlen(x) 计算字符中\0前的实际字符数
     
     */
    // 形式一：定义字符数组并逐个赋值，但要以'\0'字符结束
    char a[5];
    a[0] = 'h';
    a[1] = 'i';
    a[2] = '\0';
    cout<<a<<" "<<sizeof(a)<<" "<<strlen(a)<<endl;
    
    // 形式二：定义数组的同时为数组赋值，
    // 元数个数不足数组长度时其余默认为'\0'字符或为0
    char b[5] = {'h','i',',','h','\0'};
    cout<<b<<" "<<sizeof(b)<<" "<<strlen(b)<<endl;
    
    char b2[5] = {'h','i','\0'};
    cout<<b2<<" "<<sizeof(b2)<<" "<<strlen(b2)<<endl;
    
    // 形式三：定义数组，长度由内容决定
    char c[] = {'h','i','\0'};
    cout<<c<<" "<<sizeof(c)<<" "<<strlen(c)<<endl;
    
    // 形式四：定义字符数组，直接赋值为字符串，默认会加上'\0'字符
    char d[] = "hi";
    cout<<d<<" "<<sizeof(d)<<" "<<strlen(d)<<endl;
    
    // 理解：输出以'\0'字符结束
    char e[10] = {'h','e','l','l','o','\0','h','i','\0'};
    cout<<e<<" "<<sizeof(e)<<" "<<strlen(e)<<endl;
    return 0;
}