我知道您可以使用string.format方法。但是，您如何在C ++中执行此操作？是否可以使我可以将字节转换为十六进制？只需要将8个字节长的数据转换为十六进制，我该怎么做？
int ar[] = { 20, 30, 40, 50, 60, 70, 80, 90 };
const int siz_ar = sizeof(ar) / sizeof(int);
for (int i = 0; i < siz_ar; ++i)
cout << ar[i] << " ";
cout << endl;
for (int i = 0; i < siz_ar; ++i)
cout << hex << setfill('0') << setw(2) << ar[i] << " ";
cout << endl;
非常简单
输出：
20 30 40 50 60 70 80 90
14 1e 28 32 3c 46 50 5a
char buffer [17];
buffer[16] = 0;
for(j = 0; j < 8; j++)
sprintf(&buffer[2*j], "%02X", data[j]);
您可以使用C ++ 20
来完成，这与C＃中的String.Format
std::string s = std::format("{:x}", std::byte(42)); // s == 2a
相似：std::format
ultil
std::format可广泛可用。
std::string s = fmt::format("{:x}", std::byte(42)); // s == 2a
std::string s = fmt::format("{:02x}", std::byte(42));
std::format
C：
static void print_buf(const char *title, const unsigned char *buf, size_t buf_len)
{
size_t i = 0;
fprintf(stdout, "%s\n", title);
for(i = 0; i < buf_len; ++i)
fprintf(stdout, "%02X%s", buf[i],
( i + 1 ) % 16 == 0 ? "\r\n" : " " );
}
C++：
void print_bytes(std::ostream& out, const char *title, const unsigned char *data, size_t dataLen, bool format = true) {
out << title << std::endl;
out << std::setfill('0');
for(size_t i = 0; i < dataLen; ++i) {
out << std::hex << std::setw(2) << (int)data[i];
if (format) {
out << (((i + 1) % 16 == 0) ? "\n" : " ");
}
}
out << std::endl;
}
在现代C ++中打印任意结构 到目前为止，所有答案都只能告诉您如何打印整数数组，但是鉴于我们知道它的大小，我们也可以打印任何任意结构。下面的示例创建了这样的结构，并通过其字节迭代指针，将其打印到输出：
#include <iostream>
#include <iomanip>
#include <cstring>
using std::cout;
using std::endl;
using std::hex;
using std::setfill;
using std::setw;
using u64 = unsigned long long;
using u16 = unsigned short;
using f64 = double;
struct Header {
u16 version;
u16 msgSize;
};
struct Example {
Header header;
u64 someId;
u64 anotherId;
bool isFoo;
bool isBar;
f64 floatingPointValue;
};
int main () {
Example example;
// fill with zeros so padding regions don't contain garbage
memset(&example, 0, sizeof(Example));
example.header.version = 5;
example.header.msgSize = sizeof(Example) - sizeof(Header);
example.someId = 0x1234;
example.anotherId = 0x5678;
example.isFoo = true;
example.isBar = true;
example.floatingPointValue = 1.1;
cout << hex << setfill('0'); // needs to be set only once
auto *ptr = reinterpret_cast<unsigned char *>(&example);
for (int i = 0; i < sizeof(Example); i++, ptr++) {
if (i % sizeof(u64) == 0) {
cout << endl;
}
cout << setw(2) << static_cast<unsigned>(*ptr) << " ";
}
return 0;
}
这是输出：
05 00 24 00 00 00 00 00
34 12 00 00 00 00 00 00
78 56 00 00 00 00 00 00
01 01 00 00 00 00 00 00
9a 99 99 99 99 99 f1 3f
version占据了2个字节（
05 00），然后再添加2个字节（
msgSize），然后是4个字节的填充物，之后又来了
24 00（
someIdanotherId78 56 00 00 00 00 00 00也请注意，所有值均表示为
小调（最不重要的字节首先），因为这是在Intel平台上编译并运行的。
这是nibble到十六进制方法的修改版本isFoo我不知道一个更好的方法：
01您可以使用nibble对十六进制方法
加快速度
isBar使用C ++流并恢复状态之后
main.cpp
01
floatingPointValue输出：
void hexArrayToStr(unsigned char* info, unsigned int infoLength, char **buffer) {
const char* pszNibbleToHex = {"0123456789ABCDEF"};
int nNibble, i;
if (infoLength > 0) {
if (info != NULL) {
*buffer = (char *) malloc((infoLength * 2) + 1);
buffer[0][(infoLength * 2)] = 0;
for (i = 0; i < infoLength; i++) {
nNibble = info[i] >> 4;
buffer[0][2 * i] = pszNibbleToHex[nNibble];
nNibble = info[i] & 0x0F;
buffer[0][2 * i + 1] = pszNibbleToHex[nNibble];
}
} else {
*buffer = NULL;
}
} else {
*buffer = NULL;
}
}
在Ubuntu 16.04，GCC6.4.0.进行测试。
unsigned char byData[xxx];
int nLength = sizeof(byData) * 2;
char *pBuffer = new char[nLength + 1];
pBuffer[nLength] = 0;
for (int i = 0; i < sizeof(byData); i++)
{
sprintf(pBuffer[2 * i], "%02X", byData[i]);
}
，大写，并被空间隔开。
unsigned char byData[xxx];
const char szNibbleToHex = { "0123456789ABCDEF" };
int nLength = sizeof(byData) * 2;
char *pBuffer = new char[nLength + 1];
pBuffer[nLength] = 0;
for (int i = 0; i < sizeof(byData); i++)
{
// divide by 16
int nNibble = byData[i] >> 4;
pBuffer[2 * i] = pszNibbleToHex[nNibble];
nNibble = byData[i] & 0x0F;
pBuffer[2 * i + 1] = pszNibbleToHex[nNibble];
}
示例：
#include <iomanip>
#include <iostream>
int main() {
int array[] = {0, 0x8, 0x10, 0x18};
constexpr size_t size = sizeof(array) / sizeof(array[0]);
// Sanity check decimal print.
for (size_t i = 0; i < size; ++i)
std::cout << array[i] << " ";
std::cout << std::endl;
// Hex print and restore default afterwards.
std::ios cout_state(nullptr);
cout_state.copyfmt(std::cout);
std::cout << std::hex << std::setfill('0') << std::setw(2);
for (size_t i = 0; i < size; ++i)
std::cout << array[i] << " ";
std::cout << std::endl;
std::cout.copyfmt(cout_state);
// Check that cout state was restored.
for (size_t i = 0; i < size; ++i)
std::cout << array[i] << " ";
std::cout << std::endl;
}
0 8 16 24
00 8 10 18
0 8 16 24
可启用代码hereY.