编程实现：把十进制数(long型)分别以二进制和十六进制形式输出，不能使用printf系列。
实现了unsigned long型的转换。
// 十进制转换为二进制，十进制数的每1bit转换为二进制的1位数字
<pre lang="c" escaped="true" line="1">
char *int_to_bin(unsigned long data)
{
int bit_num = sizeof(unsigned long) * 8;
char *p_bin = new char[bit_num+1];
p_bin[bit_num] = ' ';
for (unsigned int i = 0; i < bit_num; ++i)
{
p_bin[i] = data << i >> (bit_num-1);
if (p_bin[i] == 0)
p_bin[i] = '0';
else if (p_bin[i] == 1)
p_bin[i] = '1';
else
p_bin[i] = 'a';
}
return p_bin;
}
</pre>
// 十进制转换为十六进制，十进制数的每4bit转换为十六进制的1位数字
<pre lang="c" escaped="true" line="1">
char *int_to_hex(unsigned long data)
{
int bit_num = sizeof(unsigned long) * 8;
char *p_hex = new char[sizeof(unsigned long)*8/4+3];
p_hex[0] = '0';
p_hex[1] = 'x';
p_hex[bit_num/4+2] = ' ';
char *p_tmp = p_hex + 2;
for (unsigned int i = 0; i < bit_num/4; ++i)
{
p_tmp[i] = data << (4*i) >> (bit_num-4);
if (p_tmp[i] >= 0 && p_tmp[i] <= 9)
p_tmp[i] += '0';
else if (p_tmp[i] >= 10 && p_tmp[i] <= 15)
p_tmp[i] = p_tmp[i] - 10 + 'A';
}
return p_hex;
}
</pre>