How to convert a string into a hexadecimal and store that hexadecimal value into a string in c-CodePudding

I want to store the hex values into a string, but I don't know to do that when my string is not giving me the hex values when it is printed out. I'm pretty sure it has something to do with hex, but I don't know how to get those int values that print out the correct hex values to be stored into a string without it being changed.

I tried different ways of manipulating this and searched on the web but have not found much of a solution in solving this.

#include <iostream>
#include <string>
#include <sstream>
#include <iterator>
#include <iomanip>
#include <vector>
#include <stdlib.h>

using std::cout;
using std::endl;
using std::string;
using std::hex;
using std::stringstream;

using namespace std;

int main(){
        string s2 = "HelloWorld";

        cout << "string: " << s2 << endl;
        cout << "hexval: ";
        vector<int> character; // converting each character to its ascii value
        string bytes;
        for(int i = 0; i < s2.size(); i  ) {
            character.push_back(int(s2[i]));
            bytes = to_string(character.at(i));
            cout << hex << character.at(i) << " ";
            cout << bytes << endl;
        }
        cout << endl;
        cout << bytes << endl;
        
    return 0;
}

Here is the output that 'bytes' my string is printing out:

Left is the hexadecimals and right is the string. Two different values. How can I store these hexadecimals that is being converted from a string be stored into a string as a hexadecimal value?

CodePudding user response：

I see 2 different ways:

The first one uses a char array and writes to it with sprintf with %X.

The second way uses a stringstream and streams the int values into it with the hex specifier. You can get the string with the .str() method of stringstream.

#include <iostream>
#include <string>
#include <sstream>
#include <iterator>
#include <iomanip>
#include <vector>
#include <stdlib.h>

using std::cout;
using std::endl;
using std::string;
using std::hex;
using std::stringstream;

using namespace std;

int main(){
    string s2 = "HelloWorld";

    cout << "string: " << s2 << endl;
    string result;
    for(int i = 0; i < s2.size(); i  ) {
        char buffer[20];
        sprintf(buffer, "%X ", s2[i]);
        result  = buffer;
    }
    cout << "hexval1: " << result << endl;

    stringstream res;
    for (int val : s2)
        res << hex << val << " ";

    cout << "hexval2: " << res.str() << endl;

    return 0;
}