Java 之进制转换

//十进制转十六进制

import java.util.Scanner;
public class Main{
public static void main(String[] args){
Scanner input = new Scanner(System.in);
int n;
n=input.nextInt();
System.out.println(Integer.toHexString(n).toUpperCase());//转换成大写字母；toLowerCase()：转换成小写的16进制；
  }
}

 //各种进制转换

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
       String c=sc.next();
       System.out.println(Integer.toHexString(c).toUpperCase());//十进制转换成十六进制
        System.out.println(Integer.toBinaryString(c).toUpperCase());//十进制转换成2进制
        System.out.println(Integer.toOctalString(c).toUpperCase());//十进制转换成八进制
       System.out.println(Integer.valueOf(c,16).toString());//十六进制转换成十进制
       String t=Integer.valueOf(c, 16).toString();
       int n=Integer.parseInt(t);//先将十六进制转换成字符串然后将字符串转换成整数
       System.out.println(Integer.toOctalString(n).toUpperCase());//整数转换成八进制
    }
}

//十六进制转八进制（太长的java不行了）用c

#include <stdio.h>
#include<cstring>
int x2i(char c)
{
    if (c >= 'A')
        return c - 55;
    else
        return c - 48;
}

int main()
{
    int i, j, n;
    char a[10][100001];
    scanf("%d", &n);
    for (i = 0; i < n; i++)
        scanf("%s", a[i]);
    for (i = 0; i < n; i++)
    {
        char* p = a[i];
        int len = strlen(p);
        if (len % 3 == 1)
        {
            printf("%o", x2i(p[0]));
            j = 1;
        }
        else if (len % 3 == 2)
        {
            printf("%o", x2i(p[0])*16+x2i(p[1]));
            j = 2;
        }
        else
        {
            printf("%o", x2i(p[0])*256+x2i(p[1])*16+x2i(p[2]));
            j = 3;
        }
        for (; j < len; j += 3)
            printf("%04o", x2i(p[j])*256+x2i(p[j+1])*16+x2i(p[j+2]));
        printf("
");
    }
    return 0;
}