📜  C++修饰符类型

📅  最后修改于: 2020-12-17 05:03:18             🧑  作者: Mango


C++允许char,intdouble数据类型在它们前面有修饰符。修饰符用于更改基本类型的含义,以使其更精确地适合各种情况的需求。

数据类型修饰符在这里列出-

  • 未签名

可以将带符号,无符号,长的修饰符应用于整数基类型。另外,有符号无符号可以应用于char,而long可以应用于double。

符号无符号的修饰符也可以用作修饰符的前缀。例如, unsigned long int

C++允许使用简写形式来声明无符号,短整数。您可以简单地使用unsigned,shortlong来表示int 。它自动暗示int 。例如,以下两个语句都声明无符号整数变量。

unsigned x;
unsigned int y;

要了解C++解释有符号整数修饰符和无符号整数修饰符的方式之间的区别,您应该运行以下简短程序-

#include 
using namespace std;
 
/* This program shows the difference between
   * signed and unsigned integers.
*/
int main() {
   short int i;           // a signed short integer
   short unsigned int j;  // an unsigned short integer

   j = 50000;

   i = j;
   cout << i << " " << j;

   return 0;
}

运行该程序时,输出如下-

-15536 50000

上面的结果是因为将50,000表示为短无符号整数的位模式被短解释为-15,536。

C++中的类型限定符

类型限定符提供有关它们之前的变量的其他信息。

Sr.No Qualifier & Meaning
1

const

Objects of type const cannot be changed by your program during execution.

2

volatile

The modifier volatile tells the compiler that a variable’s value may be changed in ways not explicitly specified by the program.

3

restrict

A pointer qualified by restrict is initially the only means by which the object it points to can be accessed. Only C99 adds a new type qualifier called restrict.