c++ int 与 byte array 互转

int to byte array 

#include <vector>
using namespace std;

vector<unsigned char> intToBytes(int paramInt)
{
     vector<unsigned char> arrayOfByte(4);
     for (int i = 0; i < 4; i++)
         arrayOfByte[3 - i] = (paramInt >> (i * 8));
     return arrayOfByte;
}

byte array to int

#include <iostream>
#include <cstring>

int main() {
    unsigned char bytes[4] = { 0xdd, 0xcc, 0xbb, 0xaa };

    int value;
    std::memcpy(&value, bytes, sizeof(int));

    std::cout << std::hex << value << '\n';
}

 实例：

int intSize = 4;

    vector<unsigned char> arrayOfByte(4);
     for (int i = 0; i < 4; i++)
         arrayOfByte[3 - i] = (intSize >> (i * 8));

     byte byteSize[4] ={ arrayOfByte[3],arrayOfByte[2],arrayOfByte[1],arrayOfByte[0]};

    int size;
    std::memcpy(&size, byteSize, sizeof(int));