Question

我的任务是将十进制数转换为基数p中的数字。用户输入p。到目前为止，这是我的代码：

for(int i = 0; i < 100; i++)
{
    if(a % p == 0)  nn[i] = '0';
    if(a % p == 1)  nn[i] = '1';
    if(a % p == 2)  nn[i] = '2';
    if(a % p == 3)  nn[i] = '3';
    if(a % p == 4)  nn[i] = '4';
    if(a % p == 5)  nn[i] = '5';
    if(a % p == 6)  nn[i] = '6';
    if(a % p == 7)  nn[i] = '7';
    if(a % p == 8)  nn[i] = '8';
    if(a % p == 9)  nn[i] = '9';
    if(a % p == 10) nn[i] = 'A';
    if(a % p == 11) nn[i] = 'B';
    if(a % p == 12) nn[i] = 'C';
    if(a % p == 13) nn[i] = 'D';
    if(a % p == 14) nn[i] = 'E';
    if(a % p == 15) nn[i] = 'F';

    a = a / p;
    if(a == 0) break;
}


for(int qq = strlen(nn) - 1; qq >= 0; qq--)
    cout << nn[qq];

其中a是十进制数，char nn是输出的保存位置。我有这个问题：程序随机输出3个符号和正确的答案。为什么会发生这种情况？如何解决？

Answer 1

问题是您的nn字符串仍未终止。在nn[i+1]='\0'之前设置break将解决此问题：

if(a==0) {
    nn[i+1] = '\0';
    break;
}

请注意，您的程序相当不理想：您可以使用字符串文字和索引，而不是设置if的大链，如下所示：

char *digits = "0123456789ABCDEF";
for(int i=0;i<100;i++) {
    nn[i]=digits[a%p];
    a=a/p;
    if(a==0) {
        nn[i+1] = '\0';
        break;
    }
}

Answer 2

只要您能找到一个代表数字的符号，这就是我刚才写的可以转换为任何基数的东西：

char* ConvertBaseN(
    uint64_t     Number,
    char*        BufArray,
    int          BufLen,
    size_t       BaseN) // 0=Maxbase
{
    BufArray[0] = '\0';

    const char Symbols[] = {
        '0', '1', '2', '3', '4', '5','6','7','8','9',
                'A', 'B', 'C', 'D', 'E','F','G','H','I','J',
                        'K','L','M','N','O','P','Q','R','S','T',
                        'U','V','W','X','Y','Z',                    'a', 'b', 'c', 'd', 'e','f','g','h','i',
                        'j','k','l','m','n','o','p','q','r','s',
                        't','u','v','w','x','y','z'
    };

    // Zero means max-base
    if (BaseN == 0) {
        BaseN = sizeof(Symbols);
    }

    size_t CharSetIndex;
    size_t BufPos = BufLen - 1;
    if (BufPos < 1) {
                throw("ConvertBaseN: Receive buffer not set"
                     "big enough to fit converted number");
    }

    BufArray[BufPos--] = '\0';

    do {
        if (BufPos == -1) {
                     throw("ConvertBaseN: Receive buffer not set"
                        "big enough to fit converted number");
        }
        CharSetIndex = Number % BaseN;
        Number = Number / BaseN;
        if (CharSetIndex < 0) {
            Number = Number + 1;
            CharSetIndex += (BaseN*-1);
        }
        BufArray[BufPos--] = Symbols[CharSetIndex];
    } while (Number != 0);

    return BufArray + BufPos + 1;
}

十进制到任何基数＆lt; 17计算器c ++

2 个答案: