/* 范例：3-15 */
#include <stdio.h>
void main(void)
{
long int a; /* 定义变量a为long int类型 */
short int b; /* 定义变量b为short int类型 */
printf("long int = %d bytes\n", sizeof(a)); /* a占内存bytes数*/
printf("short int = %d bytes\n", sizeof(b)); /* b占内存bytes数*/
signed int c; /* 定义变量c为signed int类型 */
unsigned int d; /* 定义变量d为unsigned int类型 */
printf("signed int = %d bytes\n", sizeof(c));/* c占内存bytes数 */
printf("unsigned int = %d bytes\n", sizeof(d)); /* d占多少bytes */
signed long int e; /* 定义变量e为signed long int类型 */
unsigned long int f; /* 定义变量f为unsigned long int类型 */
printf("signed long int = %d bytes\n", sizeof(e));
/* e占内存多少bytes */
printf("unsigned long int = %d bytes\n", sizeof(f));
/* f占内存多少bytes */
signed short int g; /* 定义变量g为signed short int类型 */
unsigned short int h; /* 定义变量h为unsigned short int类型 */
printf("signed short int = %d bytes\n", sizeof(g));
/* g占内存多少bytes */
printf("unsigned short int = %d bytes\n", sizeof(h));
/* h占内存多少bytes */
unsigned x; /* 等同于unsigned int x; */
signed y; /* 等同于signed int y; */
long z; /* 等同于long int z; */
short v; /* 等同于 short int v; */
printf("unsigned = %d\n", sizeof(x)); /* unsigned x占内存多少bytes */
printf("signed = %d\n", sizeof(y)); /* signed y占内存多少bytes */
printf("long = %d\n", sizeof(z)); /* long z占内存多少bytes */
printf("short = %d\n", sizeof(v)); /* short v占内存多少bytes */
/* 标识浮点数类型的方式,标识char(字符类型)的方式 */
printf("\nunsigned char = %d bytes", sizeof(unsigned char));
printf("\nsigned char = %d bytes", sizeof(signed char));
printf("\nfloat = %d bytes", sizeof(float));
printf("\ndouble = %d bytes", sizeof(double));
printf("\nlong double = %d bytes\n", sizeof(long double));
/* char基本数据类型 */
/* 定义变量ch为char类型，并设初值是字符'B' */
char ch = 'B';
/* 定义变量asc为char类型，并设初值是数值66，数值66在char类型代表ASCII码，也是等于字符'B' */
char asc = 66;
printf("\n变量ch:%c\n变量asc:%c\n", ch, asc);
/* float基本数据类型 */
float i = 62.2; /* 一般基本浮点数类型，将a定义为浮点数类型 */
float j = 38.7; /* 将b定义为浮点数类型 */
float currency = 6.226E+02; /* 将currency变量定义为浮点数类型并设初值，初值以科学符号表示 */
printf("\nFloat i = %f", i); /* 使用%f浮点数各格式化符号对应到变量a */
printf("\nFloat j = %f", j); /* 使用%f浮点数各格式化符号对应到变量b */
printf("\nFloat i-j = %f", i-j); /* 使用加减运算符做a-b */
printf("\nFloat currency = %f", currency);
/* 使用%f浮点数各格式化符号打印到变量currency */
printf("\nFloat currency-(i+j)=%f", currency-(i+j));
getchar();
}
程序执行结果 ﹕
long int = 4 bytes
short int = 2 bytes
signed int = 4 bytes
unsigned int = 4 bytes
signed long int = 4 bytes
unsigned long int = 4 bytes
signed short int = 2 bytes
unsigned short int = 2 bytes
unsigned = 4
signed = 4
long = 4
short = 2
unsigned char = 1 bytes
signed char = 1 bytes
float = 4 bytes
double = 8 bytes
long double = 10 bytes
变量ch:B
变量asc:B
Float i = 62.200001
Float j = 38.700001
Float i-j = 23.500000
Float currency = 622.599976
Float currency-(i+j)=521.699974