一个static_cast引发的char转int问题
写了一段程序，放在某个群里，一同学说我这里用staic_cast有问题，不安全！

还请大家指点指点！

C/C++ code

// 读取出来大于'A'--17小于'a'的要重新计算值inline int CalcHigh_a( const char strHex ){    return static_cast<int>( strHex ) - CALCLETTER;}// 读取出来大于9小于'A'的要重新计算值inline int CalcHigh_A( const char strHex ){    return static_cast<int>( strHex ) - CALCHIGH;}

附上完整的代码：-------------我是觉得写得有点不太好看，需要怎么调整一下？

C/C++ code

#include "stdafx.h"#include "iostream"using namespace std;#define TRANSPOSEDIGIT         4// assist function#define DECIMALLENGTH0     1#define DECIMALLENGTH1     2#define DECIMALLENGTH2     3#define DECIMALLENGTH3     4#define CONVERT                    48#define CALCHIGH                ( 48 + 7 )#define CALCLETTER                ( 48 + 7 + 32 )#define LIMITNINE                16#define LIMITA                        31// 读取出来大于'A'--17小于'a'的要重新计算值inline int CalcHigh_a( const char strHex ){    return static_cast<int>( strHex ) - CALCLETTER;}// 读取出来大于9小于'A'的要重新计算值inline int CalcHigh_A( const char strHex ){    return static_cast<int>( strHex ) - CALCHIGH;}// 计算十六进制字符串的值int CalcStrDecimal( const char* strHex, const int nHexLength ){    int iResult = 0;    int ii = 0;    if ( DECIMALLENGTH0 == nHexLength )    {        ii = static_cast<int>( strHex[ 0 ] ) - CONVERT;        if ( ii > LIMITNINE && ii < LIMITA )        {            ii = CalcHigh_A( strHex[ 0 ] );        }        else if ( ii > LIMITA )        {            ii = CalcHigh_a( strHex[ 0 ] );        }        iResult += ii;    }    else if ( DECIMALLENGTH1 == nHexLength )    {        for ( int i = 0; i < nHexLength; i++ )        {            ii = static_cast<int>( strHex[ i ] ) - CONVERT;            if ( ii > LIMITNINE && ii < LIMITA )            {                ii = CalcHigh_A( strHex[ 0 ] );            }            else if ( ii > LIMITA )            {                ii = CalcHigh_a( strHex[ 0 ] );            }            switch( i )            {            case 0:                ii = ii << TRANSPOSEDIGIT;                break;            default:                break;            }            iResult += ii;        }    }    else if ( DECIMALLENGTH2 == nHexLength )    {        for ( int i = 0; i < nHexLength; i++ )        {            ii = static_cast<int>( strHex[ i ] ) - CONVERT;            if ( ii > LIMITNINE && ii < LIMITA )            {                ii = CalcHigh_A( strHex[ 0 ] );            }            else if ( ii > LIMITA )            {                ii = CalcHigh_a( strHex[ 0 ] );            }            switch( i )            {            case 0:                ii = ii << TRANSPOSEDIGIT << TRANSPOSEDIGIT;                break;            case 1:                ii = ii << TRANSPOSEDIGIT;                break;            default:                break;            }            iResult += ii;        }    }    else if ( DECIMALLENGTH3 == nHexLength )    {        for ( int i = 0; i < nHexLength; i++ )        {            ii = static_cast<int>( strHex[ i ] ) - CONVERT;            if ( ii > LIMITNINE && ii < LIMITA )            {                ii = CalcHigh_A( strHex[ 0 ] );            }            else if ( ii > LIMITA )            {                ii = CalcHigh_a( strHex[ 0 ] );            }            switch( i )            {            case 0:                ii = ii << TRANSPOSEDIGIT << TRANSPOSEDIGIT<< TRANSPOSEDIGIT;                break;            case 1:                ii = ii << TRANSPOSEDIGIT << TRANSPOSEDIGIT;                break;            case 2:                ii = ii << TRANSPOSEDIGIT;                break;            default:                break;            }            iResult += ii;        }    }    return iResult;}int _tmain(int argc, _TCHAR* argv[]){    // length == 3//    char strTest[ 5 ] = "A202";//    char strTest[ 5 ] = "a202";//    char strTest[ 5 ] = "B202";//    char strTest[ 5 ] = "b202";//    char strTest[ 5 ] = "c202";//    char strTest[ 5 ] = "C202";//    char strTest[ 5 ] = "d202";//    char strTest[ 5 ] = "D242";//    char strTest[ 5 ] = "0202";//    int lValue = CalcStrDecimal( strTest, 4 );//    char strTest[ 5 ] = "002";    char strTest[ 5 ] = "A22";//    char strTest[ 5 ] = "AAA";    int lValue = CalcStrDecimal( strTest, 3 );//    char strTest[ 5 ] = "02";//    char strTest[ 5 ] = "a2";//    char strTest[ 5 ] = "AA";//    int lValue = CalcStrDecimal( strTest, 2 );    //    char strTest[ 5 ] = "A";//    char strTest[ 5 ] = "a";//    int lValue = CalcStrDecimal( strTest, 1 );    cout << lValue << endl;    return 0;}// hex202 == int514 
 

[解决办法]
呃，没看出来有啥问题
[解决办法]
没看出来static_cast成int有啥问题。
char表示的整数值范围是int的真子集。
倒是这里干嘛这么麻烦，还依赖基本字符集中某些元素的连续性……直接用<cchar>里的一些函数不行么？
[解决办法]
完全没有问题，直接赋值都行的。int完全能兼容char
[解决办法]
strtol
[解决办法]
你自己很享受造轮子的过程，加油吧
[解决办法]

探讨

引用:
strtol


现在用的好像不是string。

[解决办法]

探讨

引用:
没看出来static_cast成int有啥问题。
char表示的整数值范围是int的真子集。
倒是这里干嘛这么麻烦，还依赖基本字符集中某些元素的连续性……直接用<cchar>里的一些函数不行么？


这个怎么说？cchar>里的一些函数？

[解决办法]
参考：
区别：static _cast、dynamic _cast、reinterpret_cast和const_cast
[解决办法]
看不出来什么问题