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String and Character Manipulation

String and Character Manipulation. C-style Strings ( ntcas ). C++ Standard Library Strings (a.k.a. Standard String Class). char name[10] = “Clayton”; #include <string> using std::string; ... string name = “Clayton”;. std::string. #include <string> using std::string;

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String and Character Manipulation

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  1. String and Character Manipulation

  2. C-style Strings (ntcas) C++ Standard Library Strings (a.k.a. Standard String Class) char name[10] = “Clayton”; #include <string> using std::string; ... string name = “Clayton”;

  3. std::string #include <string> using std::string; int main() { string name = “Clayton”; cout << name.length();

  4. 7

  5. std::string input limitations string name; cout << “What’s your name? ”; cin >> name; cout << name << endl;

  6. std::string input limitations User enters: Pattie Boyd string name; cout << “What’s your name? ”; cin >> name; cout << name << endl;

  7. std::string input limitations System outputs: Pattie string name; cout << “What’s your name? ”; cin >> name; cout << name << endl;

  8. std::string input limitations string name; string hometown; cout << “What’s your name? ”; cin >> name; cout << “What is your hometown?”; cin >> hometown;

  9. std::string input limitations System outputs: What’s your name? string name; string hometown; cout << “What’s your name? ”; cin >> name; cout << “What is your hometown?”; cin >> hometown;

  10. std::string input limitations User enters: James Marshall string name; string hometown; cout << “What’s your name? ”; cin >> name; cout << “What is your hometown?”; cin >> hometown;

  11. std::string input limitations System places “James Marshall” into the input buffer string name; string hometown; cout << “What’s your name? ”; cin >> name; cout << “What is your hometown?”; cin >> hometown;

  12. std::string input limitations System pulls “James” from the buffer and into name string name; string hometown; cout << “What’s your name? ”; cin >> name; cout << “What is your hometown?”; cin >> hometown;

  13. std::string input limitations System outputs: What is your hometown? string name; string hometown; cout << “What’s your name? ”; cin >> name; cout << “What is your hometown?”; cin >> hometown;

  14. std::string input limitations System does not wait for the user input string name; string hometown; cout << “What’s your name? ”; cin >> name; cout << “What is your hometown?”; cin >> hometown;

  15. std::string input limitations Instead “Marshall” is pulled from the buffer and into hometown string name; string hometown; cout << “What’s your name? ”; cin >> name; cout << “What is your hometown?”; cin >> hometown;

  16. std::string input fix // getline(input_stream,string_var,delimiter_char); string name; string hometown; cout << “What’s your name? ”; getline(cin, name, ‘\n’); cout << “What is your hometown?”; getline(cin, hometown, ‘\n’); cout << “Name: “ << name; cout << “Hometown: “ << hometown;

  17. std::string input fix // getline(input_stream,string_var,delimiter_char); string name; string hometown; cout << “What’s your name? ”; getline(cin, name, ‘\n’); cout << “What is your hometown?”; getline(cin, hometown, ‘\n’); cout << “Name: “ << name; cout << “Hometown: “ << hometown;

  18. std::string input fix // getline(input_stream,string_var,delimiter_char); string name; string hometown; cout << “What’s your name? ”; getline(cin, name, ‘\n’); cout << “What is your hometown?”; getline(cin, hometown, ‘\n’); cout << “Name: “ << name; cout << “Hometown: “ << hometown;

  19. std::string input fix // getline(input_stream,string_var,delimiter_char); string name; string hometown; cout << “What’s your name? ”; getline(cin, name, ‘\n’); cout << “What is your hometown?”; getline(cin, hometown, ‘\n’); cout << “Name: “ << name; cout << “Hometown: “ << hometown;

  20. std::string input fix Delimiter Character is NOT included in input; it’s discarded. // getline(input_stream,string_var,delimiter_char); string name; string hometown; cout << “What’s your name? ”; getline(cin, name, ‘\n’); cout << “What is your hometown?”; getline(cin, hometown, ‘\n’); cout << “Name: “ << name; cout << “Hometown: “ << hometown;

  21. std::string input fix System outputs: What’s your name? // getline(input_stream,string_var,delimiter_char); string name; string hometown; cout << “What’s your name? ”; getline(cin, name, ‘\n’); cout << “What is your hometown?”; getline(cin, hometown, ‘\n’); cout << “Name: “ << name; cout << “Hometown: “ << hometown;

  22. std::string input fix User enters: Janis Joplin // getline(input_stream,string_var,delimiter_char); string name; string hometown; cout << “What’s your name? ”; getline(cin, name, ‘\n’); cout << “What is your hometown?”; getline(cin, hometown, ‘\n’); cout << “Name: “ << name; cout << “Hometown: “ << hometown;

  23. std::string input fix System outputs: What is your hometown? // getline(input_stream,string_var,delimiter_char); string name; string hometown; cout << “What’s your name? ”; getline(cin, name, ‘\n’); cout << “What is your hometown?”; getline(cin, hometown, ‘\n’); cout << “Name: “ << name; cout << “Hometown: “ << hometown;

  24. std::string input fix User enters: Port Arthur // getline(input_stream,string_var,delimiter_char); string name; string hometown; cout << “What’s your name? ”; getline(cin, name, ‘\n’); cout << “What is your hometown?”; getline(cin, hometown, ‘\n’); cout << “Name: “ << name; cout << “Hometown: “ << hometown;

  25. std::string input fix System outputs: Janis Joplin // getline(input_stream,string_var,delimiter_char); string name; string hometown; cout << “What’s your name? ”; getline(cin, name, ‘\n’); cout << “What is your hometown?”; getline(cin, hometown, ‘\n’); cout << “Name: “ << name; cout << “Hometown: “ << hometown;

  26. std::string input fix System continues output: Janis JoplinPort Arthur // getline(input_stream,string_var,delimiter_char); string name; string hometown; cout << “What’s your name? ”; getline(cin, name, ‘\n’); cout << “What is your hometown?”; getline(cin, hometown, ‘\n’); cout << “Name: “ << name; cout << “Hometown: “ << hometown;

  27. std::string alternative fix string name; string hometown; cout << “What’s your name? ”; getline(cin, name); cout << “What is your hometown?”; getline(cin, hometown); cout << “Name: “ << name; cout << “Hometown: “ << hometown;

  28. std::string more input nuances string name; int age; cout << “What’s your age? ”; cin >> age; cout << “What’s your name? ”; getline(cin, name);

  29. std::string more input nuances System outputs: What’s your age? string name; int age; cout << “What’s your age? ”; cin >> age; cout << “What’s your name? ”; getline(cin, name);

  30. std::string more input nuances User enters: 8 string name; int age; cout << “What’s your age? ”; cin >> age; cout << “What’s your name? ”; getline(cin, name);

  31. std::string more input nuances System places “8\n” into the input buffer string name; int age; cout << “What’s your age? ”; cin >> age; cout << “What’s your name? ”; getline(cin, name);

  32. std::string more input nuances System pulls “8” from the buffer and into age string name; int age; cout << “What’s your age? ”; cin >> age; cout << “What’s your name? ”; getline(cin, name);

  33. std::string more input nuances System outputs: What’s your name? string name; int age; cout << “What’s your age? ”; cin >> age; cout << “What’s your name? ”; getline(cin, name);

  34. std::string more input nuances System does not wait for the user input string name; int age; cout << “What’s your age? ”; cin >> age; cout << “What’s your name? ”; getline(cin, name);

  35. std::string more input nuances Instead it pulls “\n” from the buffer into name and getline is finished string name; int age; cout << “What’s your age? ”; cin >> age; cout << “What’s your name? ”; getline(cin, name);

  36. std::string vsC-string(ntca) string sname; const int SIZE = 80; char cname[SIZE]; cout << “What’s your given name? ”; getline(cin, sname); cout << “What’s your family name? ”; cin.getline(cname, SIZE-1); //different syntax!!

  37. more C-string getline const int SIZE = 10; char name[SIZE]; cout << “What’s your name? ”; cin.ignore(500, ‘\n’); cin.getline(name, SIZE-1); cout << name << endl;

  38. more C-string getline [0] [1] [2] [3] [4] [5] [6] [7] [8] [9] ? ? ? ? ? ? ? ? ? ? const int SIZE = 10; char name[SIZE]; cout << “What’s your name? ”; cin.ignore(500, ‘\n’); cin.getline(name, SIZE-1); cout << name << endl;

  39. more C-string getline System outputs: What’s your name? [0] [1] [2] [3] [4] [5] [6] [7] [8] [9] ? ? ? ? ? ? ? ? ? ? const int SIZE = 10; char name[SIZE]; cout << “What’s your name? ”; cin.ignore(500, ‘\n’); cin.getline(name, SIZE-1); cout << name << endl;

  40. more C-string getline System clears any extraneous \n from the input buffer [0] [1] [2] [3] [4] [5] [6] [7] [8] [9] ? ? ? ? ? ? ? ? ? ? const int SIZE = 10; char name[SIZE]; cout << “What’s your name? ”; cin.ignore(500, ‘\n’); cin.getline(name, SIZE-1); cout << name << endl;

  41. more C-string getline User enters: Chimley [0] [1] [2] [3] [4] [5] [6] [7] [8] [9] C h i m l e y \0 ? ? const int SIZE = 10; char name[SIZE]; cout << “What’s your name? ”; cin.ignore(500, ‘\n’); cin.getline(name, SIZE-1); cout << name << endl;

  42. more C-string getline System outputs: Chimley [0] [1] [2] [3] [4] [5] [6] [7] [8] [9] C h i m l e y \0 ? ? const int SIZE = 10; char name[SIZE]; cout << “What’s your name? ”; cin.ignore(500, ‘\n’); cin.getline(name, SIZE-1); cout << name << endl;

  43. Extraction vs. getline The extraction operator (cin>>variable) will always skip leading whitespace and leave \n in the buffer. The getline functions will read leading whitespace and will not leave the \n in the buffer. Rule: always know what is in your input buffer.

  44. #include<cctype> • toupper(char) • returns the uppercase of arg sent toupper('a'); -> 'A‘ • tolower(char) • similar • isupper(char) • returns bool: true if uppercase isupper('a'); -> false • islower(char) • similar • isalpha(char) • similar • isdigit(char) • similar • ispunct(char) • returns bool: true if punctuation ispunct('!'); -> true • isspace(char) • returns bool: true if whitespace – space, newline, tab

  45. C-string Manipulation inti = 0, count = 0; char ntca[20] = “Hello! Hi.”; while (ntca[i] != ‘\0’) { if (ispunct(ntca[i]))         count++; i++; } cout<<count<<endl;

  46. 2

  47. C-string Manipulation inti = 0, count = 0; char ntca[20] = “Hello! Hi.”; while (ntca[i] != ‘\0’) { if (isspace(ntca[i]))         count++; i++; } cout<<count<<endl;

  48. 1

  49. C-string Manipulation inti = 0, count = 0; char ntca[20] = “Hello! Hi.”; while (ntca[i] != ‘\0’) { ntca[i] = toupper(ntca[i]); i++; } cout<<ntca<<endl;

  50. HELLO! HI.

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