sizeof

1. sizeof 函式可以查看變數、常數及資料型態所佔的位元組數。
2. 範例：查詢各種資料型態所佔 bytes 數。

   [dywang@dyw219 zzz]$ vim sizeof1.c
   [dywang@dyw219 zzz]$ cat sizeof1.c
   #include <stdio.h>
   
   main() {
   	printf("sizeof(char) = %d\n", sizeof(char));
   	printf("sizeof(short) = %d\n", sizeof(short));
   	printf("sizeof(int) = %d\n", sizeof(int));
   	printf("sizeof(long) = %d\n", sizeof(long));
   	printf("sizeof(float) = %d\n", sizeof(float));
   	printf("sizeof(double) = %d\n", sizeof(double));
   }
   

3. 編譯成功

   [dywang@dyw219 zzz]$ gcc -o sizeof1 sizeof1.c
   

4. 執行結果與上節列表吻合嗎？

   [dywang@dyw219 zzz]$ ./sizeof1 
   sizeof(char) = 1
   sizeof(short) = 2
   sizeof(int) = 4
   sizeof(long) = 8
   sizeof(float) = 4
   sizeof(double) = 8