Question

我想知道字符变量名称的简短区别，例如以＆＃39;＆amp;＆＃39;开头。并以如下字母开头：

char &c = 'a'; char a = 'a';

变量＆amp; c和a。

之间的短暂区别是什么

Answer 1

我可以保证您的编译器会拒绝char &c = 'a'; 在C ++中，您还可以为现有变量或函数定义引用，而不是定义指针（char *c = &a）。通过在引用名称前添加＆符号来定义引用。与指针区分，引用必须引用给定变量。此外，一旦定义了引用，就无法更改它。请参阅以下示例。

// I'll use char in the examples
char a = 'a', aa = 'z';
char *b1 = &a;  // OK, defines pointer b1 pointing to a
char *b2;       // OK, defines pointer b2 but not assigning an address
char &c1 = a;   // OK, c1 is a reference to a
char &c2;       // Wrong. A reference must have a referee
char &c3 = 'c'; // Wrong. Referee must be LHS
int x = 0;
char& c3 = x;   // Wrong. c3 and x type must match

// b1 is of type "char*", c1 is of type "char&", effectively the same as "char"
a = 'd'; cout << *b1 << c1; // Output: dd
*b1 = 'e'; cout << a << c1; // Output: ee
cout << sizeof(a) << " " << sizeof(b1) << " " << sizeof(c1);
                            // Output: 1 4 1 (or "1 8 1" on a 64-bit system)
b1 = &aa; cout << *b1;      // Output: z
&c1 = aa;                   // Wrong. Can't reassign references
c1 = aa; cout << c1;        // Output: z (Seems OK)
cout << a;                  // Output: z (Oops, original a is also changed)

如果我们通过开始＆＃39;＆amp;＆＃39;来声明一个char变量会发生什么？在C ++中？

1 个答案: