C++如何將十六進制字符串轉換為二進制字符串

更新時間：2023年08月02日 08:35:59 作者：花好約猿上王者

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十六進制字符串轉換為二進制字符串

一種簡單的方法將十六進制字符串轉為二進制字符串，不限制十六進制的字節(jié)數(shù)。

源代碼

傳入的十六進制字符串需要轉換為大寫！(%X, toupper())。

string GetBinaryStringFromHexString (string strHex)
{
    string sReturn = "";
    unsigned int len = strHex.length();
    for (unsigned int i = 0; i<len; i++)
    {
        switch ( strHex[i])
        {
            case '0': sReturn.append ("0000"); break;
            case '1': sReturn.append ("0001"); break;
            case '2': sReturn.append ("0010"); break;
            case '3': sReturn.append ("0011"); break;
            case '4': sReturn.append ("0100"); break;
            case '5': sReturn.append ("0101"); break;
            case '6': sReturn.append ("0110"); break;
            case '7': sReturn.append ("0111"); break;
            case '8': sReturn.append ("1000"); break;
            case '9': sReturn.append ("1001"); break;
            case 'A': sReturn.append ("1010"); break;
            case 'B': sReturn.append ("1011"); break;
            case 'C': sReturn.append ("1100"); break;
            case 'D': sReturn.append ("1101"); break;
            case 'E': sReturn.append ("1110"); break;
            case 'F': sReturn.append ("1111"); break;
        }
    }
    return sReturn;
}

十六進制字符串轉二進制字符串1的個數(shù)

優(yōu)化版

建立十六進制字符串字符“0-F” 對應二進制中1的個數(shù)的映射數(shù)組

代碼如下：

#include<iostream>
#include<string>
using namespace std;
int main(){
    string inputHex;
    cin >> inputHex;
    int bitOneNumber[16] = {0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4};
    inputHex = inputHex.substr(2);
    int cnt = 0;
    for(auto ch : inputHex){
        if(ch >= '0' && ch <= '9')
            cnt += bitOneNumber[ch - '0'];
        else if(ch >= 'a' && ch <= 'f')
            cnt += bitOneNumber[ch - 'a' + 10];
        else
            return -1;
    }
    cout << cnt <<  endl;
    system("pause");
    return 0;
}

十六進制字符串轉為二進制字符串

遍歷統(tǒng)計1的個數(shù)

#include<iostream>
#include<string>
using namespace std;
string HexStrToBinStr(string& inputHex){
    string binStr;
    for(auto ch : inputHex){
        switch (ch)
        {
        case '0' : binStr += "0000"; break;
        case '1' : binStr += "0001"; break;
        case '2' : binStr += "0010"; break;
        case '3' : binStr += "0011"; break;
        case '4' : binStr += "0100"; break;
        case '5' : binStr += "0101"; break;
        case '6' : binStr += "0110"; break;
        case '7' : binStr += "0111"; break;
        case '8' : binStr += "1000"; break;
        case '9' : binStr += "1001"; break;
        case 'a' : binStr += "1010"; break;
        case 'b' : binStr += "1011"; break;
        case 'c' : binStr += "1100"; break;
        case 'd' : binStr += "1101"; break;
        case 'e' : binStr += "1110"; break;
        case 'f' : binStr += "1111"; break;
        default:
            break;
        }
    }
    return binStr;
}
int main(){
    string inputHex;
    cin >> inputHex;
    inputHex = inputHex.substr(2);
    string binStr = HexStrToBinStr(inputHex);
    int cnt = 0;
    for(auto ch : binStr)
        if(ch == '1')
            ++cnt;
    cout << cnt << endl;
    cout << binStr << endl;
    system("pause");
    return 0;
}

二進制字符串轉十進制字符串

#include<iostream>
#include<string>
using namespace std;
//十六進制字符串串轉二進制
string HexStrToBinStr(string& inputHex){
    string binStr;
    for(auto ch : inputHex){
        switch (ch)
        {
        case '0' : binStr += "0000"; break;
        case '1' : binStr += "0001"; break;
        case '2' : binStr += "0010"; break;
        case '3' : binStr += "0011"; break;
        case '4' : binStr += "0100"; break;
        case '5' : binStr += "0101"; break;
        case '6' : binStr += "0110"; break;
        case '7' : binStr += "0111"; break;
        case '8' : binStr += "1000"; break;
        case '9' : binStr += "1001"; break;
        case 'a' : binStr += "1010"; break;
        case 'b' : binStr += "1011"; break;
        case 'c' : binStr += "1100"; break;
        case 'd' : binStr += "1101"; break;
        case 'e' : binStr += "1110"; break;
        case 'f' : binStr += "1111"; break;
        default:
            break;
        }
    }
    return binStr;
}
//二進制轉十進制
struct decStr{
    int len;
    char decstr[100000];
    decStr() : len(0){
        for(int i = 0; i < 100000; ++i)
            decstr[i] = 0;
    }
};
void addCurNumToDecStr(decStr& data, int num){
    for(int i = 0; i < data.len; ++i)
        data.decstr[i] *= 2;
    data.decstr[0] += num;
    for(int i = 0; i < data.len; ++i){
        data.decstr[i + 1] += data.decstr[i] / 10;
        data.decstr[i] %= 10;
    }
    if(data.decstr[data.len] != 0) ++data.len;
}
string assicTostr(decStr&data){
    string decstr;
    for(int i = data.len - 1; i >= 0; --i){
        decstr += data.decstr[i] + '0';
    }
    return decstr;
}
string BinStrToDecStr(string& binStr){
    decStr data;
    for(int i = 0; i < binStr.size(); ++i){
        addCurNumToDecStr(data, binStr[i] == '1' ? 1 : 0);    
    }
    string decstr = assicTostr(data);
    return decstr;
}
int main(){
    string inputHex;
    cin >> inputHex;
    inputHex = inputHex.substr(2);
    string binStr = HexStrToBinStr(inputHex);
    int cnt = 0;
    for(auto ch : binStr)
        if(ch == '1')
            ++cnt;
    cout << cnt << endl;
    cout << binStr << endl;
    string decstr = BinStrToDecStr(binStr);
    cout << decstr << endl;
    system("pause");
    return 0;
}