C ++: how to convert an int into four bytes ?, Int bytes

C ++: how to convert an int into four bytes ?, Int bytes

As we all know, an int or unsigned int is composed of four bytes (C/C ++ Learning Guide, Chapter 3rd, section 3.2.3: Memory view of variables)

For example,

Int n = sizeof (int); // n is 4

You can also clearly see the four bytes in the memory. (C/C ++ Learning Guide, Appendix: VC2008 debugging method)

But the question is: how to convert the code into four bytes?

Method 1: memcpy

This method is violent and unscientific. Try it first.

Unsigned int a = 0x12345678;

Unsigned char buf [4];

Memcpy (buf, & a, 4 );

Check whether the value of the four elements in the buf array is 0x78 0x56 0x34 0x12 (well, small end, this is a defect, the expected result is actually buf [0] = 0x12 buf [1] = 0x34 buf [2] = 0x56 buf [4] = 0x78)

Method 2: formal method (C/C ++ Learning Guide, Chapter 1, Section 6th)

Buf [0] = a> 24;

Buf [1] = a> 16;

Buf [2] = a> 8;

Buf [3] =;

Use your VC to see if it is your intention. Check it in the debugging status. Do not use printf any more.

No thanks, you should!