c语言 int与byte[]互相转换

gdb调试

root@ubuntu:/media/mtk6795/alps/sunwave_pub# gcc -g test.c 
root@ubuntu:/media/mtk6795/alps/sunwave_pub# gdb ./a.out 
GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2.1) 7.4-2012.04
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://bugs.launchpad.net/gdb-linaro/>...
Reading symbols from /media/mtk6795/alps/sunwave_pub/a.out...done.
(gdb) start
Temporary breakpoint 1 at 0x40054c: file test.c, line 6.
Starting program: /media/mtk6795/alps/sunwave_pub/a.out 

Temporary breakpoint 1, main () at test.c:6
6		int a =257; 
(gdb) n
7		int a0=0,a1=0;
(gdb) 
8		unsigned char * pBuf = NULL ;
(gdb) 
9		int b=0;
(gdb) 
10		pBuf = (unsigned char*) malloc(72*128*sizeof(unsigned char));
(gdb) 
13	    pBuf[0] =(unsigned char)(a & 0xff);
(gdb) 
14		pBuf[1] = (unsigned char)((a & 0xff00) >> 8);
(gdb) 
16	    a0 = a%256;
(gdb) 
17	    a1 = a/256;
(gdb) 
19		printf("bruce int2byte  ==>> pBuf[0]=%d,pBuf[1]=%d\n",pBuf[0],pBuf[1]);
(gdb) 
bruce int2byte  ==>> pBuf[0]=1,pBuf[1]=1
20		printf("bruce int2byte  ==>> a0=%d,a1=%d\n",a0,a1);
(gdb) 
bruce int2byte  ==>> a0=1,a1=1
23		b =(int)(( pBuf[0] & 0xff )|((pBuf[1] & 0xff)<<8));
(gdb) 
24		printf("bruce byte2int  ==>> b=%d\n",b);
(gdb) 
bruce byte2int  ==>> b=257
27		return 0;
(gdb) 
28	}
(gdb)

c语言 int与byte[]互相转换

#include<stdio.h>
#include<string.h>
#include<math.h> 
#include<stdlib.h>
int main(){
	int a =257; 
	int a0=0,a1=0;
	unsigned char * pBuf = NULL ;
	int b=0;
	pBuf = (unsigned char*) malloc(72*128*sizeof(unsigned char));

	//int2byte
    pBuf[0] =(unsigned char)(a & 0xff);
	pBuf[1] = (unsigned char)((a & 0xff00) >> 8);

    a0 = a%256;
    a1 = a/256;

	printf("bruce int2byte  ==>> pBuf[0]=%d,pBuf[1]=%d\n",pBuf[0],pBuf[1]);
	printf("bruce int2byte  ==>> a0=%d,a1=%d\n",a0,a1);

    //byte2int
	b =(int)(( pBuf[0] & 0xff )|((pBuf[1] & 0xff)<<8));
	printf("bruce byte2int  ==>> b=%d\n",b);


	return 0;
}