C 数据类型

基本数据类型

数据类型指定变量将存储的信息的大小和类型。

在64位Windows系统下，基本的数据类型大小如下所示

数据类型	大小size	范围Range	描述
char	1字节	-128~127	单个字符/字母/数字/ASCII
signed char	1字节	-128~127
unsigned char	1字节	0~255
int	4字节	-2,147,483,648~2,147,483,647
signed int	4字节	-2,147,483,648~2,147,483,647
unsigned int	4字节	0~4,294,967,295
short int	2字节	-32,768~32,767
signed short int	2字节	-32,768~32,767
unsigned short int	2字节	0~65,535
long int	4字节	-2,147,483,648~2,147,483,647	在64位Linux下大小为8字节
signed long int	4字节	-2,147,483,648~2,147,483,647	在64位Linux下大小为8字节
unsigned long int	4字节	0~4,294,967,295	在64位Linux下大小为8字节
float	4字节	±3.4 × 10^38
double	8字节	±1.7 × 10^308
long double	16字节
long long int	8字节	-9,223,372,036,854,775,808~ 9,223,372,036,854,775,807
signed long long int	8字节	-9,223,372,036,854,775,808~ 9,223,372,036,854,775,807
unsigned long long int	8字节	0~18,446,744,073,709,551,615

参考代码如下：

#include <stdio.h>

int main(){
    printf("size of char: %d\n", sizeof(char));
    printf("size of signed char: %d\n", sizeof(signed char));
    printf("size of unsigned char: %d\n", sizeof(unsigned char));
    printf("size of int: %d\n", sizeof(int));
    printf("size of signed int: %d\n", sizeof(signed int));
    printf("size of unsigned int: %d\n", sizeof(unsigned int));
    printf("size of short: %d\n", sizeof(short));
    printf("size of signed short: %d\n", sizeof(signed short));
    printf("size of unsigned short: %d\n", sizeof(unsigned short));
    printf("size of long: %d\n", sizeof(long));
    printf("size of signed long: %d\n", sizeof(signed long));
    printf("size of unsigned long: %d\n", sizeof(unsigned long));
    printf("size of float: %d\n", sizeof(float));
    printf("size of double: %d\n", sizeof(double));
    printf("size of long double: %d\n", sizeof(long double));
    printf("size of long long: %d\n", sizeof(long long));
    printf("size of signed long long: %d\n", sizeof(signed long long));
    printf("size of unsigned long long: %d\n", sizeof(unsigned long long));
    return 0;
}

在64位Windows下的输出结果：

size of char: 1
size of signed char: 1
size of unsigned char: 1
size of int: 4
size of signed int: 4
size of unsigned int: 4
size of short: 2
size of signed short: 2
size of unsigned short: 2
size of long: 4
size of signed long: 4
size of unsigned long: 4
size of float: 4
size of double: 8
size of long double: 16
size of long long: 8
size of signed long long: 8
size of unsigned long long: 8

在64位Linux下的输出结果：

size of char: 1
size of signed char: 1
size of unsigned char: 1
size of int: 4
size of signed int: 4
size of unsigned int: 4
size of short: 2
size of signed short: 2
size of unsigned short: 2
size of long: 8
size of signed long: 8
size of unsigned long: 8
size of float: 4
size of double: 8
size of long double: 16
size of long long: 8
size of signed long long: 8
size of unsigned long long: 8

基本格式说明符

每种数据类型都有不同的格式说明符。这里是其中的一些：

格式说明符	数据类型
%d 或 %i	int 整数
%f	float 单精度的十进制类型
%lf	double 高精度浮点数据或数字
%c	char 字符
%s	用于 strings

	short	int	long
8 进制	%ho	%o	%lo
10 进制	%hd	%d	%ld
16 进制	%hx 或者 %hX	` %x 或者 %X`	%lx 或者 %lX

int 整数

// 创建 整数 变量
int myNum = 5;
// 打印输出变量
printf("%d\n", myNum);

float 单精度的十进制类型

float myFloatNum = 5.99; // 浮点数
// 打印输出变量
printf("%f\n", myFloatNum);

double 双精度的十进制类型

double myDouble = 3.2325467;  
// 打印输出变量
printf("%lf\n", myDouble);

char 字符

char myLetter = 'D'; // 字符串
// 打印输出变量
printf("%c\n", myLetter);