cstring

---

1. Memory Management:

char* str = new char[strlen("Hello World") + 1];
strcpy(str, "Hello World");
// ... use str ...
delete[] str;

2. String Initialization:

char str[] = "Hello World";  // null-terminated character array
string str = "Hello World";  // C++ string

3. String Length:

size_t len = strlen("Hello World");

4. String Concatenation:

char* result = strcat(str1, str2);

5. String Comparison:

int comparison = strcmp(str1, str2);

6. Character Access:

char c = str[0];

7. String Modification:

str[0] = 'H';

8. String Copy:

strcpy(dest, src);

9. String Search:

char* found = strstr(str, "World");

10. String Tokenization:

char* token = strtok(str, " ");

11. String Formatting:

sprintf(buffer, "%.2f", value);

12. String to Number Conversion:

int num = atoi("123");

13. Number to String Conversion:

string str = to_string(123);

14. String to Floating-Point Conversion:

float f = atof("123.45");

15. Floating-Point to String Conversion:

string str = to_string(123.45);

16. String to Character Array:

char* arr = str.c_str();

17. Character Array to String:

string str(arr);

18. String Substring:

string sub = str.substr(5, 4);

19. String Find:

size_t pos = str.find("World");

20. String Replace:

str.replace(5, 4, "Universe");

21. String Trim:

str.trim();

22. String To Uppercase:

str.toUpper();

23. String To Lowercase:

str.toLower();

24. String Split:

vector<string> words = str.split(" ");

25. String Join:

string joined = str.join(words, ", ");

26. String Reverse:

reverse(str.begin(), str.end());

27. String Sort:

sort(str.begin(), str.end());

28. String Encryption:

string encrypted = encrypt(str, key);

29. String Decryption:

string decrypted = decrypt(encrypted, key);

30. String Hashing:

string hash = hash(str);

31. String Compression:

string compressed = compress(str);

32. String Decompression:

string decompressed = decompress(compressed);

33. String Conversion to Hexadecimal:

string hex = str.toHex();

34. String Conversion from Hexadecimal:

string str = hex.fromHex();

35. String Padding:

string padded = str.pad(10, '0');

36. String Truncation:

string truncated = str.truncate(10);

37. String Encoding:

string encoded = str.encode(encoding);

38. String Decoding:

string decoded = str.decode(encoding);

39. String Validation:

bool valid = str.isValid();

40. String Formatting for Numbers:

string formatted = str.format(value, "0.00");

41. String Formatting for Dates:

string formatted = str.format(date, "yyyy-MM-dd");

42. String Formatting for Currency:

string formatted = str.format(currency, "$0.00");

43. String Formatting for Percentages:

string formatted = str.format(percent, "0.00%");

44. String Formatting for Hours and Minutes:

string formatted = str.format(time, "hh:mm a");

45. String Argument Parsing:

int num = stoi(argv[1]);
string option = argv[2];

46. String Output Manipulation:

cout << left << setw(10) << str;

47. String Input Manipulation:

cin >> setw(10) >> str;

48. String Manipulation with Regular Expressions:

regex r(".*Hello.*");
regex_match(str, r);

49. String Manipulation with Boost:

boost::algorithm::trim(str);
boost::algorithm::replace_all(str, " ", "_");

50. String Manipulation with C++20:

string str(u8"你好世界");
auto result = string_view{str}.starts_with("你");