C语言，数据类型

 

#include <stdio.h>

void f0(void)
{
    printf("in linux:\n");
    printf("sizeof(char) = %d\n", sizeof(char));        
    printf("sizeof(int) = %d\n", sizeof(int));        
    printf("sizeof(short int) = %d\n", sizeof(short int));    
    printf("sizeof(long int) = %d\n", sizeof(long int));       
      
    printf("sizeof(float) = %d\n", sizeof(float)); 
       
    printf("sizeof(double) = %d\n", sizeof(double));       
    printf("sizeof(long double) = %d\n", sizeof(long double));    
    
}

void f1(void)
{
    int i = 1;
    unsigned int ui = 1;
    char c = 1;
    unsigned char uc = 1;
    short int si = 1;
    unsigned short int usi = 1;
    float f = 1;
    double d = 1;
    long double ld = 1;
    
    printf("for 1, i = %x, ui = %x\n", i, ui);  
    printf("for 1, c = %x, uc = %x\n", c, uc); 
    printf("for 1, si = %x, usi = %x\n", si, usi);
    printf("for 1, f = %x\n", f);
    printf("for 1, d = %x\n", d);
    printf("for 1, ld = %x\n", ld);
      
}
void f2()
{
    int i = -1;
    unsigned int ui = -1;
    char c = -1;
    unsigned char uc = -1;
    short int si = -1;
    unsigned short int usi = -1;
    float f = -1;
    double d = -1;
    long double ld = -1;
    
    printf("for -1, i = %x, ui = %x\n", i, ui);  
    printf("for -1, c = %x, uc = %x\n", c, uc); 
    printf("for -1, si = %x, usi = %x\n", si, usi);
    printf("for -1, f = %x\n", f);
    printf("for -1, d = %x\n", d);
    printf("for -1, ld = %x\n", ld);
    
    
    c = -255;
    uc = -255;
    printf("for -255, c = %x, uc = %x\n", c, uc);
    
    c = -128;
    uc = -128;
    printf("for -128, c = %x, uc = %x\n", c, uc);
}

void f_show1(void)
{
    printf("for -1,f_show1: uint = %x\n", (unsigned int)-1);
    printf("for -1,f_show1: int = %x\n", (int)-1);
    printf("for -1,f_show1: c = %x\n", (char)-1);    
    printf("for -1,f_show1: uc = %x\n", (unsigned char)-1);
    
    printf("for -1,f_show1: uc = %d\n", (unsigned char)-1);
}

int main()
{
    f0();
    f_show1();
    
    f1();
    f2();
    
    return 0;
}

/*
root@oucaijun:/work/dcc# gcc 1.c ;./a.out 

in linux:
sizeof(char) = 1
sizeof(int) = 4
sizeof(short int) = 2
sizeof(long int) = 4
sizeof(float) = 4
sizeof(double) = 8
sizeof(long double) = 12

//此处说明在linux系统中，对整数常数是以？方式表示
for -1,f_show1: uint = ffffffff
for -1,f_show1: int = ffffffff
for -1,f_show1: c = ffffffff
for -1,f_show1: uc = ff
for -1,f_show1: uc = 255

for 1, i = 1, ui = 1
for 1, c = 1, uc = 1
for 1, si = 1, usi = 1
for 1, f = 0
for 1, d = 0
for 1, ld = 0
for -1, i = ffffffff, ui = ffffffff
for -1, c = ffffffff, uc = ff
for -1, si = ffffffff, usi = ffff
for -1, f = 0
for -1, d = 0
for -1, ld = 0
for -255, c = 1, uc = 1
for -128, c = ffffff80, uc = 80

*/