Просмотр исходного текста страницы C++/String/char array string

==Convert char array to upper case==


   
<source lang="cpp">   
#include <iostream>
#include <string.h>
using namespace std;
struct Msg 
{
  char message[256];
  void show_message(void) { cout << message; }
};
struct UpperMsg 
{
   char message[256];
   void show_message(void) { cout << strupr(message); }
};

int main(void)
{
   Msg book = { "B" };
   UpperMsg book_upr = { "c" };
   book.show_message();
   book_upr.show_message();
}
  
    
    
  </source>


==Count spaces, punctuation, digits, and letters.==


   
<source lang="cpp">   
#include <iostream>
#include <cctype>
using namespace std;
int main() {
  const char *str = "This is a test. 1 2 3 4 5";
  int letters = 0, spaces = 0, punct = 0, digits = 0;
  cout << str << endl;
  while(*str) {
    if(isalpha(*str)) 
       ++letters;
    else if(isspace(*str)) 
       ++spaces;
    else if(ispunct(*str)) 
       ++punct;
    else if(isdigit(*str)) 
       ++digits;
    ++str;
  }
  cout << "Letters: " << letters << endl;
  cout << "Digits: " << digits << endl;
  cout << "Spaces: " << spaces << endl;
  cout << "Punctuation: " << punct << endl;
  return 0;
}
  
    
    
  </source>


==Demonstrate the basic null-terminated string functions.==


   
<source lang="cpp">   
#include <iostream>
#include <cstring>
using namespace std;
int main() {
  char strA[7] = "U";
  char strB[5] = "D";
  char strC[5] = "L";
  char strD[6] = "R";
  cout << "Here are the strings: " << endl;
  cout << "strA: " << strA << endl;
  cout << "strB: " << strB << endl;
  cout << "strC: " << strC << endl;
  cout << "strD: " << strD << "\n\n";
  cout << "Length of strA is " << strlen(strA) << endl;
  strcat(strA, strB);
  cout << "strA after concatenation: " << strA << endl;
  cout << "Length of strA is now " << strlen(strA) << endl;
  strcpy(strB, strC);
  cout << "strB now holds: " << strB << endl;
  if(!strcmp(strB, strC))
    cout << "strB is equal to strC\n";
  int result = strcmp(strC, strD);
  if(!result)
    cout << "strC is equal to strD\n";
  else if(result < 0)
    cout << "strC is less than strD\n";
  else if(result > 0)
    cout << "strC is greater than strD\n";
  return 0;
}
  
    
    
  </source>


==Filling an Array==


   
<source lang="cpp">  
#include <iostream>
using namespace std;
int main(){
    char buffer[80] = {"\0"};
    std::cout << "Enter the string: ";
    std::cin >> buffer;
    std::cout << "Here"s the buffer: " << buffer << std::endl;
    return 0;
}
  
    
  </source>


==Get the string length==


   
<source lang="cpp">  
#include <iostream>  
#include <string.h>  
using namespace std;
main(void)  
{  
  int i;  
  i = 10;  
     
  int j = 100;
     
  cout << i*j << "\n";  
     
  cout << "Enter a string: ";  
  char str[80];  
  cin >> str;  
     
  // display the string in reverse order  
  int k;  
  k = strlen(str);  
  k--;  
  while(k>=0) {  
    cout << str[k];  
    k--;  
  }  
     
  return 0;  
}
  
    
  </source>


==Operator pointer==


   
<source lang="cpp">   
#include <iostream>
#include <string.h>
using namespace std;
class Book {
  public:
    Book(char *title, char *publisher, char *author);
    void show_book(void) { 
    cout << "Book: " << title << " by " <<
        author << " Publisher: " << publisher << endl; 
  };
    operator char *();
   
  private:
    char title[64];
    char author[64];
    char publisher[64];
};
Book::Book(char *title, char *publisher, char *author)
{
   strcpy(Book::title, title);
   strcpy(Book::publisher, publisher);
   strcpy(Book::author, author);
}
Book::operator char *(void)
{
   char *ptr = new char[256]; 
   
   return(strcpy(ptr, title)); 
}

int main(void)
{
   Book myBook("A", "B","C");
   
   char *title;
   title = myBook;
   cout << "The book"s title is " << title << endl;
}
  
    
    
  </source>


==Use strlen() to get the length of a char array buffer==


   
<source lang="cpp">  
#include <iostream>
#include <string.h>
using namespace std;
int main()
{
   char buffer[80];
   do
   {
      cout << "Enter a string up to 80 characters: ";
      cin.getline(buffer,80);
      cout << "Your string is " << strlen(buffer);
      cout << " characters long." << endl;
   }while (strlen(buffer));
   return 0;
}
  
    
  </source>


==Using atoi() function==


   
<source lang="cpp">  
#include <stdlib.h>
#include <iostream>
using namespace std;
int main()
{
   char buffer[80];
   cout << "Enter a number: ";
   cin >> buffer;
   int number;
   number = atoi(buffer);
   cout << "Here"s the number: " << number << endl;
   int sum = atoi(buffer) + 5;
   cout << "Here"s sum: " << sum << endl;
   return 0;
}
  
    
  </source>


==Using strcat() and strncat().==


   
<source lang="cpp">  
#include <iostream>
#include <string.h>
using namespace std;
int main()
{
   char stringOne[255];
   char stringTwo[255];
   stringOne[0]="\0";
   stringTwo[0]="\0";
   cout << "Enter a  string: ";
   cin.getline(stringOne,80);
   cout << "Enter a second string: ";
   cin.getline(stringTwo,80);
   cout << "String One: " << stringOne << endl;
   cout << "String Two: " << stringTwo << endl;
   strcat(stringOne," ");
   strncat(stringOne,stringTwo,10);
   cout << "String One: " << stringOne << endl;
   cout << "String Two: " << stringTwo << endl;
   return 0;
}
  
    
  </source>


==Using strcpy and string terminator==


   
<source lang="cpp">  
#include <iostream>
#include <string.h>
using namespace std;
int main()
{
   char stringOne[80];
   char stringTwo[80];
   stringOne[0]="\0";
   stringTwo[0]="\0";
   cout << "String One: " << stringOne << endl;
   cout << "String Two: " << stringTwo << endl;
   cout << "Enter a string: ";
   cin.getline(stringOne,80);
   cout << "\nString One: " << stringOne << endl;
   cout << "String Two: " << stringTwo << endl;
   cout << "copying..." << endl;
   strcpy(stringTwo,stringOne);
   cout << "\nString One: " << stringOne << endl;
   cout << "String Two: " << stringTwo << endl;
   cout << "\nDone " << endl;
   return 0;
}
  
    
  </source>


==Using strcpy() to assign value from one char array to another char array==


   
<source lang="cpp">  
#include <iostream>
#include <string.h>
using namespace std;
int main()
{
   char String1[] = "this is a test";
   char String2[80] = {"\0"};
   strcpy(String2,String1);
   cout << "String1: " << String1 << endl;
   cout << "String2: " << String2 << endl;
   return 0;
}
  
    
  </source>


==Using strncpy() and string terminator==


   
<source lang="cpp">  
#include <iostream>
#include <string.h>
using namespace std;
int main()
{
   char stringOne[80];
   char stringTwo[10];
   char stringThree[80];
   stringOne[0]="\0";
   stringTwo[0]="\0";
   stringThree[0]="\0";
   cout << "String One: " << stringOne << endl;
   cout << "String Two: " << stringTwo << endl;
   cout << "String Three: " << stringThree << endl;
   cout << "Enter a long string: ";
   cin.getline(stringOne,80);
   strcpy(stringThree,stringOne);
   cout << "\nString One: " << stringOne << endl;
   cout << "String Two: " << stringTwo << endl;
   cout << "String Three: " << stringThree << endl;
   strncpy(stringTwo,stringOne,9);
   cout << "\nString One: " << stringOne << endl;
   cout << "String Two: " << stringTwo << endl;
   cout << "String Three: " << stringThree << endl;
   stringTwo[9]="\0";
   cout << "\nString One: " << stringOne << endl;
   cout << "String Two: " << stringTwo << endl;
   cout << "String Three: " << stringThree << endl;
   cout << "\nDone." << endl;
   return 0;
}
  
    
  </source>


==Using strncpy() to assign one char array to another char array==


   
<source lang="cpp">  
#include <iostream>
#include <string.h>
int main()
{
    const int MaxLength = 80;
    char String1[] = "this is a test";
    char String2[MaxLength+1] = {"\0"};
    strncpy(String2, String1, MaxLength);    
    std::cout << "String1: " << String1 << std::endl;
    std::cout << "String2: " << String2 << std::endl;
    return 0;
}
  
    
  </source>