C语言学习-关于C语言中sizeof关键字的测试

 1 #include <stdio.h>
 2 #include <malloc.h>
 3 
 4 typedef struct point
 5 {
 6     int x;
 7     int y;
 8     char *description;
 9     char *message;
10 } Point;
11 
12 typedef union job
13 {
14     char *name;
15     int salary;
16     int  worker_no;
17 
18 
19 } Job;
20 
21 main()
22 {
23     char* arrays[] = { "Abc", "abc", "1bc", "123" };
24 
25     int n = 0;
26     printf("int sizeof(%d) = %d\n",n, sizeof(n) );
27 
28     unsigned int m = 0;
29     printf("unsigned sizeof(%u) = %d\n",m,sizeof(m));
30 
31     char c = ‘\0‘;
32     printf("char sizeof(%c) = %d\n", c,sizeof(c));
33 
34     long lo = 0;
35     printf("long sizeof(%ld) = %d\n", lo, sizeof(lo) );
36 
37     unsigned long ulo = 0;
38     printf("unsigned long sizeof(%ld) = %d\n", ulo, sizeof(ulo) ); 
39     
40     char *pString = "Hello World";
41 
42     int iInt = 12;
43     int  *pInt = &iInt;
44 
45     printf("pointer size(*pInt) = %d\n", sizeof(pInt) );
46     printf("pointer sizeof(*p) = %d\n", sizeof(pString));
47     printf("pointer sizeof(arrays)= %d\n", sizeof(*arrays));
48 
49     int length = sizeof(arrays)/sizeof(*arrays);
50 
51     printf("arrays.length = %d\n", length );
52 
53     int i;
54     for( i = 0 ; i<length; i++)
55     {
56         printf("arrays[%d] = %s\n", i, *(arrays + i) );
57     }
58 
59     Point *p;
60     p = malloc(sizeof(struct point));
61     p->x = 100;
62     p->y = 100;
63     p->description = pString;
64 
65     printf("point x = %d, y = %d, description = %s\n", p->x, p->y, p->description );
66     printf("struct sizeof(struct point) = %d\n", sizeof(struct point) );
67     printf("struct pointer sizeof(p) = %d\n", sizeof(p) );
68 
69     printf("union sizeof(job) = %d\n", sizeof(Job) );
70 
71     char name[10];
72     printf("char arrays sizeof(name) = %d\n", sizeof(name));
73 
74     Job *job = malloc(sizeof(union job));
75     printf("union pointer sizeof(job) = %d\n", sizeof(job) );
76 
77     printf("The Father of the C programming Language Information\n");
78     printf("-------------------------------------------------------\n");
79 
80     job->name = "Dennis Ritchie";
81     printf("Name : %s\n" , job->name );
82     
83     job->salary = 1000000000;
84     printf("He‘s salary =%d\n" , job->salary );
85 
86     short sInt = 0;
87 
88     printf("short sizeof(short) = %d\n", sizeof sInt );
89 
90     float f = 0.0f;
91     printf("float sizeof(float) = %d\n", sizeof f );
92 
93     double d  = 0.0;
94 
95     printf("double sizeof(double) = %d\n", sizeof d );
96 
97 
98 }