在我的文本编码器程序中找不到错误

只是为了好玩，我一直在研究一个文本编码程序，它会打乱文本。 我已经让它几乎完美无缺地工作，但似乎无法解决一个错误。 基本上，文本在大多数情况下都会正确编码和解码，除了偶尔，程序会解码一个字母不合适的字符串。 代码有点丑陋，我没有尝试清理它，因为我仍在解决错误，所以我对此表示歉意。 它在部分中的复制和粘贴也很差，因此在我使其正常工作后，优化的机会对我来说将是巨大的。 我有一种感觉，我知道错误在哪里，但是进行我认为需要进行的更正会导致无休止的循环。 以下是底部存储在注释中的一些输出的代码：

#include <iostream>
using namespace std;
void FillKey(char Key2[]);
void Encrypt();
void EncryptMessage(char Key3[], char Input2[], char MessageEncrypted2[]);
void Decrypt();
void DecryptMessage(char Key4[], char CodedInput2[], char NormalOutput2[]);
char ReturnDecodedCharacter(char Key5[], char Character);
const int STRING_SIZE=500;
const int ASCII_RANGE_SIZE_94=94;//Range from ASCII value 32 to 126 = 94
const int SHIFT_SET_32=32;//Move range up 32 values form (0-93) to (32 to 126)
int main()
{
    int Choice;
    do
    {
        cout << "Press 1 to encrypt"      << endl;
        cout << "Press 2 to decrypt"      << endl;
        cout << "Press other key to quit" << endl << endl;
        cout << "Choice: ";
        cin >> Choice;
        if (Choice == 1)
            Encrypt();
        else if (Choice == 2)
            Decrypt();
    }
    while (Choice==1 || Choice == 2);
}
void Encrypt()
{
    int  SecretNumber;
    char Key[ASCII_RANGE_SIZE_94]={0};//One larger 0 - 93, not using 0
    char Input[STRING_SIZE]={0};
    char MessageEncrypted[STRING_SIZE]={0};
    cout << "nEnter Secret Number: ";
    cin >> SecretNumber;
    cin.ignore(1);//removes newline from input buffer
    srand(SecretNumber);//Seed number for my random number generator
    FillKey(Key);
    cout << "nInput message: ";
    cin.getline(Input, STRING_SIZE);
    EncryptMessage(Key, Input, MessageEncrypted);
    cout << "nEncrypted Message(copy inside of parenthesis): " << "(" << MessageEncrypted << ")" << endl << endl;
}
void FillKey(char Key3[])
{
    int RandomNumber;
    int KeySpot, j;
    for (KeySpot=0; KeySpot<=ASCII_RANGE_SIZE_94; ++KeySpot)
    {
        RandomNumber = SHIFT_SET_32+rand()%ASCII_RANGE_SIZE_94;//0-93, then shifts up to 32-126 ASCII range
        for (j=0; j<=KeySpot; ++j)//this bit of code checks to make sure new rand number isn't already used before
        {
            if (Key3[j] == RandomNumber)
            {
                RandomNumber = SHIFT_SET_32+rand()%ASCII_RANGE_SIZE_94;//0-93, then shifts up to 32-126
                j=0;
            }
        }
        Key3[KeySpot] = (char) RandomNumber;
    }
}
void EncryptMessage(char Key3[], char Input2[], char MessageEncrypted2[])
{
    for (int i=0; Input2[i]; ++i)
    {
        MessageEncrypted2[i]= Key3[((int) Input2[i])-SHIFT_SET_32];//-32 to get range back into 1-95 (range of Key)
    }
}
void Decrypt()
{
    int SecretNumber;
    char Key[ASCII_RANGE_SIZE_94]={0};
    char EncryptedMessage[STRING_SIZE]={0};
    char DecodedMessage[STRING_SIZE]={0};
    cout << "nEnter Secret Number: ";
    cin >> SecretNumber;
    cin.ignore(1);//removes newline from input buffer
    srand(SecretNumber);//Seed number for random number generator
    FillKey(Key);
    cout << "nInput message to decode: ";
    cin.getline(EncryptedMessage, STRING_SIZE);
    DecryptMessage(Key, EncryptedMessage, DecodedMessage);
    cout << "nDecoded Message: " << DecodedMessage << endl << endl;
}
void DecryptMessage(char Key4[], char EncryptedMessage2[], char DecodedMessage2[])
{
    for (int i=0; EncryptedMessage2[i]; ++i)
    {
        DecodedMessage2[i] = ReturnDecodedCharacter(Key4, EncryptedMessage2[i]);
    }
}
char ReturnDecodedCharacter(char Key5[], char Character)
{
    for (int Count=0; Count<=ASCII_RANGE_SIZE_94; ++Count)
    {
        if ((int) Character == Key5[Count])
        {
            return (char) Count+SHIFT_SET_32;//+32 to get back into 32-126 ASCII range
        }
    }
    return 0;
}
/*
Press 1 to encrypt
Press 2 to decrypt
Press other key to quit
Choice: 2
Enter Secret Number: 1
Input message to decode: abcdefghijklmnopqrstuvqwyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890
Decoded Message: Yj.63;nQb_ d"*!yTuc'8rTWi~1/|^ta5:?s+ODJwge42X,%q$SEvNZ9-h=kFL
Press 1 to encrypt
Press 2 to decrypt
Press other key to quit
Choice: 1
Enter Secret Number: 2
Input message: abcdefghijklmnopqrstuvqwyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890
Encrypted Message(copy inside of parenthesis): (oZs?=LtFPSk<B +j]&xf!}]1"yq;zQm8:>|T7_56VRH{9D-/*aOdbGCgAnJuv)
Press 1 to encrypt
Press 2 to decrypt
Press other key to quit
Choice: 2
Enter Secret Number: 2
Input message to decode: oZs?=LtFPSk<B +j]&xf!}]1"yq;zQm8:>|T7_56VRH{9D-/*aOdbGCgAnJuv
Decoded Message: abcdefghijklmnopqrstuvqwyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890
Press 1 to encrypt
Press 2 to decrypt
Press other key to quit
Choice: 1
Enter Secret Number: 3
Input message: abcdefghijklmnopqrstuvqwyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890
Encrypted Message(copy inside of parenthesis): (w?oGY`hn5Ty% LZ$qrDHR$"!F=WX}IV-Nf|g&+(Ps.pM*S)1t/e2@9v067{KC)
Press 1 to encrypt
Press 2 to decrypt
Press other key to quit
Choice: 2
Enter Secret Number: 3
Input message to decode: w?oGY`hn5Ty% LZ$qrDHR$"!F=WX}IV-Nf|g&+(Ps.pM*S)1t/e2@9v067{KC
Decoded Message: abcdefghijklmnopqrstuvqwyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890
Press 1 to encrypt
Press 2 to decrypt
Press other key to quit
Choice: 1
Enter Secret Number: 4
Input message: abcdefghijklmnopqrstuvqwyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890
Encrypted Message(copy inside of parenthesis): (2RQ%?u*"_yNXs!=t;VWb9);]:+#>dqv$wU7(EiP[JgGI&pxmh4 eafk}0^1ln)
Press 1 to encrypt
Press 2 to decrypt
Press other key to quit
Choice: 2
Enter Secret Number: 4
Input message to decode: 2RQ%?u*"_yNXs!=t;VWb9);]:+#>dqv$wU7(EiP[JgGI&pxmh4 eafk}0^1ln
Decoded Message:  bcdefghijklmnopqrstuvqwyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890
Press 1 to encrypt
Press 2 to decrypt
Press other key to quit
Choice:
*/

如果您注意到，最后一个字符串（秘密编号为 4）没有正确转换并丢失了首字母"a"。 我认为错误出在 void FillKey 函数中 - 在 if 语句中if (Key3[j] == RandomNumber)我创建了一个新的随机数并设置j=0如果任何新生成的随机数与键中以前的任何随机数完全相同（显然不能有相同的字符两次）。 所以我的想法是，j 被设置为 0，但在 for 循环之后，它被递增并变成 1。 所以程序没有检查Key3[3]中的重复项，所以我将语句更改为 j=-1 ，以预测它并在 for 循环后将其恢复为零，但随后程序卡住了并且永远不存在循环。

任何建议将不胜感激。