递归算法实现进制转换

1、十进制转换成二进制【递归法】

#include <stdio.h>

int decimal_to_binary(unsigned int number)
{
    return number == 0 ? 0 : number % 2 + 10 * decimal_to_binary(number / 2);
}

void test()
{
    const int sets[][2] = 
    {
        {0, 0}, {1, 1}, {2, 6}, {3, 11}, {5, 60}, {6, 10}, {7, 100},
    };

    for (int i = 0, size = sizeof(sets) / sizeof(sets[0]); i < size; ++i)
    {
        printf("res:%d\n",decimal_to_binary(sets[i][0]));
    }
}

int main()
{
    test();
    return 0;
}

测试结果：

binary[0] = 0
binary[1] = 1
binary[2] = 10
binary[3] = 11
binary[4] = 100
binary[5] = 110
binary[6] = 111
 

2、十进制转换成八进制【递归法】

#include <stdio.h>

int decimal_to_octal(int decimal)
{
    if ((decimal < 8) && (decimal > 0))
    {
        return decimal;
    }
    else if (decimal == 0)
    {
        return 0;
    }
    else
    {
        return ((decimal_to_octal(decimal / 8) * 10) + decimal % 8);
    }
}

int main()
{
    int octalNumber, decimalNumber;
    printf("\nEnter your decimal number : ");
    scanf("%d", &decimalNumber);
    octalNumber = decimal_to_octal(decimalNumber);
    printf("\nThe octal of %d is : %d", decimalNumber, octalNumber);

    return 0;
}

测试结果：

Enter your decimal number : 100

The octal of 100 is : 144

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