将整数值分配给 char 数组元素

Question

程序目标是将十进制转换为十六进制1）我在将整数值分配给字符数组元素时遇到问题。我正在获取我的数组数值的符号。2） 如何将我的数组初始化为空格？以摆脱数组元素中的垃圾和旧数据。3）有人可以解释我的问题是什么吗？使用整数和字符？4） cout 是我问题的一部分吗？

#include "stdafx.h"
#include <iostream>
#include <iomanip>
#include <math.h>
int main()
{
using namespace std;
// binary declarations
int x, i, z, n, remainder;
int result = 0;
bool loop_cond, remainder_found, octval_found;
// octal declarations
int octalval,octresult,octremainder,temp_octalval;
int octloop_cnt;
bool oct_loop;
octresult = 0;
// hexadecimal declarations
int hexval, hexremainder, temp_hexval;
int hexloop_cnt;
bool hex_loop,hexval_found;
char hexresult[5] = {" "};
cout << "decimal" << "t" << "binary" << "t"<< "octal"<<"t"<<"hexadecimal"<< endl;
for (i = 1; i <= 256; i++){  
hexloop_cnt = 0;
octremainder = 0;
hexval_found = false;
hex_loop = true;
hexloop_cnt = 0;
while (hex_loop != false){
if (hexval_found != true){
    hexval = i / 16;
    hexremainder = i % 16;
}
else {
    temp_hexval  = hexval;
    hexval = hexval / 16;
    hexremainder = temp_hexval % 16;
}

if (hexval == 0){
    switch (hexremainder){
    case 10:
        hexresult[hexloop_cnt] = 'A';
        break;
    case 11:
        hexresult[hexloop_cnt] = 'B';
        break;
    case 12:
        hexresult[hexloop_cnt] = 'C';
        break;
    case 13:
        hexresult[hexloop_cnt] = 'D';
        break;
    case 14:
        hexresult[hexloop_cnt] = 'E';
        break;
    case 15:
        hexresult[hexloop_cnt] = 'F';
        break;
    default:
        hexresult[hexloop_cnt] = (char)hexremainder;
        break;
    }//end switch
    hex_loop = false;
}//end if
if ((hexval < 16) && (hexval > 0)){
    switch (hexremainder){
    case 10:
        hexresult[hexloop_cnt] = 'A';
        break;
    case 11:
        hexresult[hexloop_cnt] = 'B';
        break;
    case 12:
        hexresult[hexloop_cnt] = 'C';
        break;
    case 13:
        hexresult[hexloop_cnt] = 'D';
        break;
    case 14:
        hexresult[hexloop_cnt] = 'E';
        break;
    case 15:
        hexresult[hexloop_cnt] = 'F';
        break;
    default:
        hexresult[hexloop_cnt] = static_cast<char>(hexremainder);
        break;
    }//end switch
    hexloop_cnt++;
    switch (hexval){
    case 10:
        hexresult[hexloop_cnt] = 'A';
        break;
    case 11:
        hexresult[hexloop_cnt] = 'B';
        break;
    case 12:
        hexresult[hexloop_cnt] = 'C';
        break;
    case 13:
        hexresult[hexloop_cnt] = 'D';
        break;
    case 14:
        hexresult[hexloop_cnt] = 'E';
        break;
    case 15:
        hexresult[hexloop_cnt] = 'F';
        break;
    default:
        hexresult[hexloop_cnt] = static_cast<char>(hexval);
        break;
    }//end switch
    hex_loop = false;
  } //end if
if ((hexval >= 16)){
    switch (hexremainder){
    case 10:
        hexresult[hexloop_cnt] = 'A';
        break;
    case 11:
        hexresult[hexloop_cnt] = 'B';
        break;
    case 12:
        hexresult[hexloop_cnt] = 'C';
        break;
    case 13:
        hexresult[hexloop_cnt] = 'D';
        break;
    case 14:
        hexresult[hexloop_cnt] = 'E';
        break;
    case 15:
        hexresult[hexloop_cnt] = 'F';
        break;
    default:
        hexresult[hexloop_cnt] = static_cast<char>(hexremainder);
        break;
    }//end switch
    hexval_found = true;
}//end if 
hexloop_cnt++;
} //endwhile

    cout << i << "t" << result <<"t" << octresult<<"t" << hexresult<< endl;
    result = 0;
    octresult = 0;
//      hexresult[5] = { ' ', ' ', ' ', ' ', ' ' };
}

cin.clear();
cin.ignore(255, '/n');
cin.get();
return 0;
}

Answer 1

你不能这样做

hexresult[hexloop_cnt] = (char)hexremainder;

你需要做

hexresult[hexloop_cnt] = hexremainder + '0';

为什么？好吧，想想如果十六进制= 1。字符"1"的 ascii 不是0x01而是0x31。因此，您需要向该值添加0x30。"0"表示0x30（查看 ASCII 表以了解 http://www.asciitable.com/发生了什么）

Answer 2

std：：cout 可能是问题所在。以这个例子为例。

#include <iostream>
int main()
{
    unsigned char c = 239;
    std::cout << c << "n";
    std::cout << static_cast<int>(c) << "n";
    return 0;
}

输出：

./a.out 
�
239