CareerCup

short convert_short(short in) 
{ 
  short out; 
  char *p_in = (char *) ∈ 
  char *p_out = (char *) &out; 
  p_out[0] = p_in[1]; 
  p_out[1] = p_in[0];   
  return out; 
} 

long convert_long(long in) 
{ 
  long out; 
  char *p_in = (char *) ∈ 
  char *p_out = (char *) &out; 
  p_out[0] = p_in[3]; 
  p_out[1] = p_in[2]; 
  p_out[2] = p_in[1]; 
  p_out[3] = p_in[0];   
  return out; 
}

union { uint8 nBytes[2]; uint16 hBytes; } DATA;
uint16 htons(uint16 hostBytes) {
DATA d.hBytes = hostBytes;
d.nBytes[0]=((hostBytes >>8) &0xFF);
d.nBytes[1]=((hostBytes & 0xFF)<<8)
return d.nBytes[0] | d.nBytes[1];
}

union { uint8 nBytes[2]; uint16 hBytes; } DATA;
uint16 htons(uint16 hostBytes) {
DATA d.hBytes = hostBytes;
uint8 temp [2]= {nBytes[1],nBytes[0]};
return *((uint16*)&temp[0]);
}

#include<stdio.h>

int main()
{
 int x=0x12345678,final=0x0000,i;
int mask=0x000f,num=28;
int common;
for(i=0;i<8;i++)
{
common=x&mask;
x=x>>4;
final=final|(common<<num);
common=common<<(32-num);
num=num-4;
}
printf("final=%x",final);

return 0;
}

typedef union data
{
struct databyte{
char a;
char b;
char c;
char d;
} h;
int e;
};
int LittletoBigUnion(int g )
{
union data f;
f.e=g;
f.e=((f.h.a)<<24)|((f.h.b)<<16)|((f.h.c)<<8)|((f.h.d));
return f.e;
}
int LittletoBig(int a )
{
int b= ((a&0xff)<<24)|((a&0xff00)<<8)|((a&0xff0000)>>8)|((a&0xff000000)>>24);
return b;
}

typedef union data
{
struct databyte{
char a;
char b;
char c;
char d;
} h;
int e;
};
int LittletoBigUnion(int g )
{
union data f;
f.e=g;
f.e=((f.h.a)<<24)|((f.h.b)<<16)|((f.h.c)<<8)|((f.h.d));
return f.e;
}
int LittletoBig(int a )
{
int b= ((a&0xff)<<24)|((a&0xff00)<<8)|((a&0xff0000)>>8)|((a&0xff000000)>>24);
return b;
}

does this suffice ? not sure.

union { uint8 nBytes[2]; uint16 hBytes; } DATA;
uint16 htons(uint16 hostBytes) {
	DATA d.hBytes = hostBytes;
	return d.nBytes[1] | d.nBytes[0];
}