如何跨preT号码正确（十六进制，华侨城，DEC） [英] How to interpret numbers correctly (hex, oct, dec)

问题描述

我想编写一个程序，它的输入 - 十六进制，八进制，和小数 - ，将它们存储在整数变量，并输出其转换为十进制的形式一起。例如：

用户输入：0×43，0123，65

程序输出：

  0×43进制转换为十进制67
0123八进制转换为十进制83
65（十进制）转换为65（十进制）
 

所以，很显然，我需要一种方法来除preT的数字，但我不知道如何去这样做。我已经试过各种方法，如阅读他们到一个函数，并将它们转换成字符串，反之亦然（见的这里 code的例子），但国米preting的数字总是需要转换成某种格式，象垃圾一样清除原来的输入。

我能想到的唯一的事情是重载一个>>操作员每次读取一个字符，如果它看到0x或0在输入的开始则将其读入之前，它存储了整个输入字符串一个int。然后程序会以某种方式有输出时，以确定正确的机械手。

不知道是否有这样做一个简单的方法，任何帮助是AP preciated。

编辑：这已经解决了，但我还是决定发布code中如果有人有兴趣

 的#includestd_lib_facilities.h无效number_sys（NUM字符串，字符串和放大器; S）
{
  如果（NUM [0] =='0'和;及（NUM [1] ='×'和;！试验＃[1] =X）！）S =八进制;
  否则如果（NUM [0] =='0'和;及（NUM [1] =='X'|| NUM [1] =='X'））S =十六进制数;
  否则S =十进制;
}诠释的main（）
{
    COUT＆LT;＆LT; 十六进制数字的输入，DEC，或十月使用0XX取消\\ n;
    串;    而（CIN＆GT;＆胺a）{
    如果（A ==0XX）打破;
    串atype的;
    number_sys（一，atype的）;    INT ANUM = strtol将（a.c_str（），NULL，0）;    COUT＆LT;＆LT; A＆LT;＆LT;运输及工务局局长（20-则为a.length（））≤;＆下; atype的＆LT;＆LT;运输及工务局局长（20）所述;＆下; 转换为＆LT;＆LT;运输及工务局局长（10）
         ＆LT;＆LT; ANUM＆LT;＆LT;运输及工务局局长（10）所述;＆下; 小数\\ N的;
                 }    keep_window_open（）;
}
 

解决方案

看看strtol函数。

 的char * ARGS [3] = {0×43，0123，65};
对（INT I = 0;我3; ++ⅰ）{
  长整型值=与strtol（参数[I]，NULL，0）;
  的printf（％S转换到％D十进制\\ n，ARGS [I]，值）;
}
 

输出：

  0x43中转换为十进制67
0123转换为十进制83
65转换为65（十进制）
 

I'm trying to write a program that takes input of - hexadecimals, octals, and decimals -, stores them in integer variables, and outputs them along with their conversion to decimal form. For example:

User inputs: 0x43, 0123, 65

Program outputs:

0x43 hexadecimal converts to 67 decimal
0123 octal converts to 83 decimal
65 decimal converts to 65 decimal

So obviously I need a way to interpret the numbers, but I'm not sure how to go about doing it. I've tried various methods such as reading them into a function and converting them into a string, and vice versa (see here for code examples), but interpreting the numbers always requires conversion to some format that trashes the original input.

The only thing I can think of is overloading a >> operator that reads a character at a time and if it sees 0x or 0 at the beginning of the input then it stores the whole input into a string before it is read into an int. Then the program would somehow have to determine the right manipulator during output.

Not sure if there is a simpler way to do this, any help is appreciated.

Edit: This has been solved, but I decided to post the code in if anyone is interested.

#include "std_lib_facilities.h"

void number_sys(string num, string& s)
{
  if(num[0] == '0' && (num[1] != 'x' && num[1] != 'X')) s = "octal";
  else if(num[0] == '0' && (num[1] == 'x' || num[1] == 'X')) s = "hexadecimal";
  else s = "decimal";
}

int main()
{
    cout << "Input numbers in hex, dec, or oct. Use 0xx to cancel.\n";
    string a;

    while(cin >> a){
    if(a == "0xx")break;
    string atype;
    number_sys(a, atype);

    int anum = strtol(a.c_str(), NULL, 0);

    cout << a << setw(20-a.length()) << atype << setw(20) << "converts to" << setw(10)
         << anum << setw(10) << "decimal\n";
                 }

    keep_window_open();
}

解决方案

Take a look at the strtol function.

char * args[3] = {"0x43", "0123", "65"};
for (int i = 0; i < 3; ++i) {
  long int value = strtol(args[i], NULL, 0);
  printf("%s converts to %d decimal\n", args[i], value);
}

Outputs:

0x43 converts to 67 decimal
0123 converts to 83 decimal
65 converts to 65 decimal

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