数组的大小及定义sizeof和strlen

char a[] = "abcd";
char b[] = {"a","b","c","e","f"};
int d = strlen(a);//4
int e = strlen(b);//16
cout << d << " " << e << endl;
cout << a[2]<<" "<<b[2]<< endl;
return 0;
char st[20] = "hello	\"; 
int d = strlen(st);
int f = sizeof(st);
cout << d <<" "<<f<< endl;//d=5,只计算hello的长度,在结尾再次添加也没有用("hello	\qqq"),只是5,只有在前面添加有用,原因是,但是后面要是数字会变,为什么?.因为遇到就结束!
//f=20,开辟的空间大小多少,就是多少,
return 0;
char st[20] = "hello	\";//7个
char st[20] = "77";//这个是7后面的转为7进制?,不清楚,实验暂时得出7后面如果不是数字7算是1个字符,如果是,则7加上后面挨着的数字算一个,大数会报错
int d = strlen(st);//为1
int f = sizeof(st);//20
cout << d <<" "<<f<< endl;

char st[20] = "89A77";
int d = strlen(st);//4
int f = sizeof(st);

char st[20] = "89A	7";
int d = strlen(st);//5
int f = sizeof(st);
strlen("asdasde	"\wang"!	");//17每个+后边的一个算一个,\算一个,a,算一个