将静态字符数组中的字符分配给动态分配的字符数组 – 访问冲突

huangapple
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英文:

Assigning chars from static char array to dynamically allocated char array - Access violation

问题

以下是您提供的代码的翻译部分：

  1. 我是C++的新手，正在尝试一些有趣的事情。但我不明白为什么这段代码不起作用，而且抛出了访问内存违规异常。
  2. 它能工作，但当I等于6时，它会抛出异常。
  4. 我在这里做的是尝试使用128位位置数字系统进行实验。
  6. 代码 - 
  7. #include "pch.h"
  8. #include <iostream>
  10. char* Encode(unsigned long long int);
  11. unsigned long long int Decode(const char*);
  13. int main() {
  14. 	try {
  15. 		setlocale(LC_CTYPE, "rus");
  16. 		unsigned long long int Input = 1223212123412142;
  17. 		std::cout << Input << std::endl;
  18. 		char* EncodedStr = Encode(Input);
  19. 		std::cout << EncodedStr << std::endl;
  20. 		unsigned long long int Output = Decode(EncodedStr);
  21. 		std::cout << Output << std::endl;
  22. 	} catch(std::exception e) {
  23. 		std::cout << "发生异常！异常信息：" << e.what() << std::endl;
  24. 	}
  25. 	std::cin.get();
  26. }
  28. char WordMap[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'а', 'б', 'в', 'г', 'д', 'е', 'ё', 'ж', 'з', 'и', 'й', 'к', 'л', 'м', 'н', 'о', 'п', 'р', 'с', 'т', 'у', 'ф', 'х', 'ц', 'ч', 'ш', 'щ', 'ь', 'ы', 'ь', 'э', 'ю', 'я', 'А', 'Б', 'В', 'Г', 'Д', 'Е', 'Ё', 'Ж', 'З', 'И', 'Й', 'К', 'Л', 'М', 'Н', 'О', 'П', 'Р', 'С', 'Т', 'У', 'Ф', 'Х', 'Ц', 'Ч', 'Ш', 'Щ', 'Ь', 'Ы', 'Ь', 'Э', 'Ю', 'Я'};
  30. const int WordAmount = sizeof(WordMap) / sizeof(char);
  32. char* Encode(unsigned long long int Input) {
  33. 	int I = 0;
  34. 	unsigned long long int D = 0;
  35. 	unsigned long long int Previous = Input;
  36. 	while(Input > pow(WordAmount, I)) {
  37. 		I += 1;
  38. 	}
  39. 	int Size = I + 1;
  40. 	char* Encoded = new char[Size];
  41. 	std::cout << I << std::endl;
  42. 	while(I >= 0) {
  43. 		D = pow(WordAmount, I);
  44. 		std::cout << I << std::endl;
  45. 		try{
  46. 			Encoded[Size - I - 1] = WordMap[Previous / D]; // 这里抛出异常。请注意，仅当I < 8时，才会抛出异常，8是此输入中的幂的数量。这也意味着Encoded[0]和可能从0到3都被赋值，而从3到8则没有。
  47. 		} catch(...) {
  49. 		}
  50. 		Previous -= D;
  51. 		I -= 1;
  52. 	}
  53. 	return Encoded;
  54. }
  56. unsigned long long int Decode(const char* Input) {
  57. 	int I = strlen(Input);
  58. 	int K = 0;
  59. 	unsigned long long int Previous = 0;
  60. 	while(I > 0) {
  61. 		for(size_t i = 0; i < WordAmount; i++) {
  62. 			if(WordMap[i] == Input[I - 1]) {
  63. 				K = i;
  64. 				break;
  65. 			}
  66. 		}
  67. 		Previous += K * (unsigned long long int)pow(WordAmount, I - 1);
  68. 		I -= 1;
  69. 	}
  70. 	return Previous;
  71. }

希望这有助于您理解代码。如果您有任何其他问题，请随时提出。

英文:

I'm new to C++, having some fun with it. And I don't understand why this code isn't working and throwing access memory violation exception.
It works but when I is 6 it throws the exception

What I'm doing here is I'm trying to experiment with 128 position numeral system.

Code -

  1. #include &lt;iostream&gt;
  2. char* Encode(unsigned long long int);
  3. unsigned long long int Decode(const char*);
  4. int main() {
  5. try {
  6. setlocale(LC_CTYPE, &quot;rus&quot;);
  7. unsigned long long int Input = 1223212123412142;
  8. std::cout &lt;&lt; Input &lt;&lt; std::endl;
  9. char* EncodedStr = Encode(Input);
  10. std::cout &lt;&lt; EncodedStr &lt;&lt; std::endl;
  11. unsigned long long int Output = Decode(EncodedStr);
  12. std::cout &lt;&lt; Output &lt;&lt; std::endl;
  13. } catch(std::exception e) {
  14. std::cout &lt;&lt; &quot;Exception has been thrown! Exception&quot; &lt;&lt; e.what() &lt;&lt; std::endl;
  15. }
  16. std::cin.get();
  17. }
  18. char WordMap[] = {&#39;0&#39;, &#39;1&#39;, &#39;2&#39;, &#39;3&#39;, &#39;4&#39;, &#39;5&#39;, &#39;6&#39;, &#39;7&#39;, &#39;8&#39;, &#39;9&#39;, &#39;a&#39;, &#39;b&#39;, &#39;c&#39;, &#39;d&#39;, &#39;e&#39;, &#39;f&#39;, &#39;g&#39;, &#39;h&#39;, &#39;i&#39;, &#39;j&#39;, &#39;k&#39;, &#39;l&#39;, &#39;m&#39;, &#39;n&#39;, &#39;o&#39;, &#39;p&#39;, &#39;q&#39;, &#39;r&#39;, &#39;s&#39;, &#39;t&#39;, &#39;u&#39;, &#39;v&#39;, &#39;w&#39;, &#39;x&#39;, &#39;y&#39;, &#39;z&#39;, &#39;A&#39;, &#39;B&#39;, &#39;C&#39;, &#39;D&#39;, &#39;E&#39;, &#39;F&#39;, &#39;G&#39;, &#39;H&#39;, &#39;I&#39;, &#39;J&#39;, &#39;K&#39;, &#39;L&#39;, &#39;M&#39;, &#39;N&#39;, &#39;O&#39;, &#39;P&#39;, &#39;Q&#39;, &#39;R&#39;, &#39;S&#39;, &#39;T&#39;, &#39;U&#39;, &#39;V&#39;, &#39;W&#39;, &#39;X&#39;, &#39;Y&#39;, &#39;Z&#39;, &#39;а&#39;, &#39;б&#39;, &#39;в&#39;, &#39;г&#39;, &#39;д&#39;, &#39;е&#39;, &#39;ё&#39;, &#39;ж&#39;, &#39;з&#39;, &#39;и&#39;, &#39;й&#39;, &#39;к&#39;, &#39;л&#39;, &#39;м&#39;, &#39;н&#39;, &#39;о&#39;, &#39;п&#39;, &#39;р&#39;, &#39;с&#39;, &#39;т&#39;, &#39;у&#39;, &#39;ф&#39;, &#39;х&#39;, &#39;ц&#39;, &#39;ч&#39;, &#39;ш&#39;, &#39;щ&#39;, &#39;ь&#39;, &#39;ы&#39;, &#39;ь&#39;, &#39;э&#39;, &#39;ю&#39;, &#39;я&#39;, &#39;А&#39;, &#39;Б&#39;, &#39;В&#39;, &#39;Г&#39;, &#39;Д&#39;, &#39;Е&#39;, &#39;Ё&#39;, &#39;Ж&#39;, &#39;З&#39;, &#39;И&#39;, &#39;Й&#39;, &#39;К&#39;, &#39;Л&#39;, &#39;М&#39;, &#39;Н&#39;, &#39;О&#39;, &#39;П&#39;, &#39;Р&#39;, &#39;С&#39;, &#39;Т&#39;, &#39;У&#39;, &#39;Ф&#39;, &#39;Х&#39;, &#39;Ц&#39;, &#39;Ч&#39;, &#39;Ш&#39;, &#39;Щ&#39;, &#39;Ь&#39;, &#39;Ы&#39;, &#39;Ь&#39;, &#39;Э&#39;, &#39;Ю&#39;, &#39;Я&#39;};
  19. const int WordAmount = sizeof(WordMap) / sizeof(char);
  20. char* Encode(unsigned long long int Input) {
  21. int I = 0;
  22. unsigned long long int D = 0;
  23. unsigned long long int Previous = Input;
  24. while(Input &gt; pow(WordAmount, I)) {
  25. I += 1;
  26. }
  27. int Size = I + 1;
  28. char* Encoded = new char[Size];
  29. std::cout &lt;&lt; I &lt;&lt; std::endl;
  30. while(I &gt;= 0) {
  31. D = pow(WordAmount, I);
  32. std::cout &lt;&lt; I &lt;&lt; std::endl;
  33. try{
  34. Encoded[Size - I - 1] = WordMap[Previous / D]; // Here&#39;s the exception being thrown. Notice it&#39;s only when I &lt; 8, 8 is number of powers in this Input. It also means that Encoded[0] and probably from 0 to 3 are being assigned and from 3 to 8 aren&#39;t
  35. } catch(...) {
  36. }
  37. Previous -= D;
  38. I -= 1;
  39. }
  40. return Encoded;
  41. }
  42. unsigned long long int Decode(const char* Input) {
  43. int I = strlen(Input);
  44. int K = 0;
  45. unsigned long long int Previous = 0;
  46. while(I &gt; 0) {
  47. for(size_t i = 0; i &lt; WordAmount; i++) {
  48. if(WordMap[i] == Input[I - 1]) {
  49. K = i;
  50. break;
  51. }
  52. }
  53. Previous += K * (unsigned long long int)pow(WordAmount, I - 1);
  54. I -= 1;
  55. }
  56. return Previous;
  57. }

答案1

得分: 0

修复了代码，现在它可以正常工作了。问题出在算法中。

  1. #include <iostream>
  3. int Encode(unsigned long long int, char**);
  4. unsigned long long int Decode(const char*, int);
  6. using namespace std;
  8. int main() {
  9.     setlocale(LC_CTYPE, "rus");
  10.     unsigned long long int Input = 0;
  11.     unsigned long long int Output = 0;
  12.     char* EncodedStr = NULL;
  13.     int Size = 0;
  14.     while(true) {
  15.         cin >> Input;
  16.         Size = Encode(Input, &EncodedStr);
  17.         Output = Decode(EncodedStr, Size);
  18.         cout << EncodedStr << endl;
  19.         cout << Output << endl;
  20.     }
  21. }
  23. const char WordMap[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'а', 'б', 'в', 'г', 'д', 'е', 'ё', 'ж', 'з', 'и', 'й', 'к', 'л', 'м', 'н', 'о', 'п', 'р', 'с', 'т', 'у', 'ф', 'х', 'ц', 'ч', 'ш', 'щ', 'ь', 'ы', 'ь', 'э', 'ю', 'я', 'А', 'Б', 'В', 'Г', 'Д', 'Е', 'Ё', 'Ж', 'З', 'И', 'Й', 'К', 'Л', 'М', 'Н', 'О', 'П', 'Р', 'С', 'Т', 'У', 'Ф', 'Х', 'Ц', 'Ч', 'Ш', 'Щ', 'Ь', 'Ы', 'Ь', 'Э', 'Ю', 'Я'};
  24. const int WordAmount = sizeof(WordMap) / sizeof(char);
  26. int Encode(unsigned long long int Input, char** Output) {
  27.     int I = 0;
  28.     int K = 0;
  29.     unsigned long long int D = 0;
  30.     unsigned long long int Previous = Input;
  31.     while(Input > pow(WordAmount, I + 1)) {
  32.         I += 1;
  33.     }
  34.     const int Size = I + 1;
  35.     *Output = new char[Size + 1];
  36.     (*Output)[Size] = 0;
  37.     while(I >= 0) {
  38.         D = powl(WordAmount, I);
  39.         K = Previous / D;
  40.         (*Output)[Size - I - 1] = WordMap[K];
  41.         Previous -= D * K;
  42.         I -= 1;
  43.     }
  44.     return Size;
  45. }
  47. unsigned long long int Decode(const char* Input, int Size) {
  48.     int I = Size - 1;
  49.     int K = 0;
  50.     unsigned long long int Previous = 0;
  51.     while(I >= 0) {
  52.         for(size_t i = 0; i < WordAmount; i++) {
  53.             if(WordMap[i] == Input[Size - I - 1]) {
  54.                 K = i;
  55.                 break;
  56.             }
  57.         }
  58.         Previous += K * (unsigned long long int)powl(WordAmount, I);
  59.         I -= 1;
  60.     }
  61.     return Previous;
  62. }

这是已修复的代码。

英文:

Fixed the code. It works now. The problem was in algorithm

  1. #include &quot;pch.h&quot;
  2. #include &lt;iostream&gt;
  3. int Encode(unsigned long long int, char**);
  4. unsigned long long int Decode(const char*, int);
  5. using namespace std;
  6. int main() {
  7. setlocale(LC_CTYPE, &quot;rus&quot;);
  8. unsigned long long int Input = 0;
  9. unsigned long long int Output = 0;
  10. char* EncodedStr = NULL;
  11. int Size = 0;
  12. while(true) {
  13. cin &gt;&gt; Input;
  14. Size = Encode(Input, &amp;EncodedStr);
  15. Output = Decode(EncodedStr, Size);
  16. cout &lt;&lt; EncodedStr &lt;&lt; endl;
  17. cout &lt;&lt; Output &lt;&lt; endl;
  18. }
  19. }
  20. const char WordMap[] = {&#39;0&#39;, &#39;1&#39;, &#39;2&#39;, &#39;3&#39;, &#39;4&#39;, &#39;5&#39;, &#39;6&#39;, &#39;7&#39;, &#39;8&#39;, &#39;9&#39;, &#39;a&#39;, &#39;b&#39;, &#39;c&#39;, &#39;d&#39;, &#39;e&#39;, &#39;f&#39;, &#39;g&#39;, &#39;h&#39;, &#39;i&#39;, &#39;j&#39;, &#39;k&#39;, &#39;l&#39;, &#39;m&#39;, &#39;n&#39;, &#39;o&#39;, &#39;p&#39;, &#39;q&#39;, &#39;r&#39;, &#39;s&#39;, &#39;t&#39;, &#39;u&#39;, &#39;v&#39;, &#39;w&#39;, &#39;x&#39;, &#39;y&#39;, &#39;z&#39;, &#39;A&#39;, &#39;B&#39;, &#39;C&#39;, &#39;D&#39;, &#39;E&#39;, &#39;F&#39;, &#39;G&#39;, &#39;H&#39;, &#39;I&#39;, &#39;J&#39;, &#39;K&#39;, &#39;L&#39;, &#39;M&#39;, &#39;N&#39;, &#39;O&#39;, &#39;P&#39;, &#39;Q&#39;, &#39;R&#39;, &#39;S&#39;, &#39;T&#39;, &#39;U&#39;, &#39;V&#39;, &#39;W&#39;, &#39;X&#39;, &#39;Y&#39;, &#39;Z&#39;, &#39;а&#39;, &#39;б&#39;, &#39;в&#39;, &#39;г&#39;, &#39;д&#39;, &#39;е&#39;, &#39;ё&#39;, &#39;ж&#39;, &#39;з&#39;, &#39;и&#39;, &#39;й&#39;, &#39;к&#39;, &#39;л&#39;, &#39;м&#39;, &#39;н&#39;, &#39;о&#39;, &#39;п&#39;, &#39;р&#39;, &#39;с&#39;, &#39;т&#39;, &#39;у&#39;, &#39;ф&#39;, &#39;х&#39;, &#39;ц&#39;, &#39;ч&#39;, &#39;ш&#39;, &#39;щ&#39;, &#39;ь&#39;, &#39;ы&#39;, &#39;ь&#39;, &#39;э&#39;, &#39;ю&#39;, &#39;я&#39;, &#39;А&#39;, &#39;Б&#39;, &#39;В&#39;, &#39;Г&#39;, &#39;Д&#39;, &#39;Е&#39;, &#39;Ё&#39;, &#39;Ж&#39;, &#39;З&#39;, &#39;И&#39;, &#39;Й&#39;, &#39;К&#39;, &#39;Л&#39;, &#39;М&#39;, &#39;Н&#39;, &#39;О&#39;, &#39;П&#39;, &#39;Р&#39;, &#39;С&#39;, &#39;Т&#39;, &#39;У&#39;, &#39;Ф&#39;, &#39;Х&#39;, &#39;Ц&#39;, &#39;Ч&#39;, &#39;Ш&#39;, &#39;Щ&#39;, &#39;Ь&#39;, &#39;Ы&#39;, &#39;Ь&#39;, &#39;Э&#39;, &#39;Ю&#39;, &#39;Я&#39;};
  21. const int WordAmount = sizeof(WordMap) / sizeof(char);
  22. int Encode(unsigned long long int Input, char** Output) {
  23. int I = 0;
  24. int K = 0;
  25. unsigned long long int D = 0;
  26. unsigned long long int Previous = Input;
  27. while(Input &gt; pow(WordAmount, I + 1)) {
  28. I += 1;
  29. }
  30. const int Size = I + 1;
  31. *Output = new char[Size + 1];
  32. (*Output)[Size] = 0;
  33. while(I &gt;= 0) {
  34. D = powl(WordAmount, I);
  35. K = Previous / D;
  36. (*Output)[Size - I - 1] = WordMap[K];
  37. Previous -= D * K;
  38. I -= 1;
  39. }
  40. return Size;
  41. }
  42. unsigned long long int Decode(const char* Input, int Size) {
  43. int I = Size - 1;
  44. int K = 0;
  45. unsigned long long int Previous = 0;
  46. while(I &gt;= 0) {
  47. for(size_t i = 0; i &lt; WordAmount; i++) {
  48. if(WordMap[i] == Input[Size - I - 1]) {
  49. K = i;
  50. break;
  51. }
  52. }
  53. Previous += K * (unsigned long long int)powl(WordAmount, I);
  54. I -= 1;
  55. }
  56. return Previous;
  57. }

huangapple
  • 本文由 发表于 2020年1月4日 12:07:11
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  • arrays
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  • exception
  • pointers
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