PPT On C++ Strings

Presentation On C++ Strings
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C++ Strings Presentation Transcript:
1.C++ Strings

2.C++ Strings
C++ provides following two types of string representations:
The C-style character string.
The string class type introduced with Standard C++.

3.The C-Style Character String:
The C-style character string originated within the C language and continues to be supported within C++.
This string is actually a one-dimensional array of characters which is terminated by a nullcharacter '\0'. Thus a null-terminated string contains the characters that comprise the string followed by a null.
The following declaration and initialization create a string consisting of the word "Hello

4.". To hold the null character at the end of the array, the size of the character array containing the string is one more than the number of characters in the word "Hello.“
char greeting[6] = {'H', 'e', 'l', 'l', 'o', '\0'};
If you follow the rule of array initialization then you can write the above statement as follows:
char greeting[] = "Hello";

5.Actually, you do not place the null character at the end of a string constant. The C++ compiler automatically places the '\0' at the end of the string when it initializes the array. Let us try to print above mentioned string:

6.#include
using namespace std;
int main ()
{
char greeting[6] = {'H', 'e', 'l', 'l', 'o', '\0'};
cout << "Greeting message: ";
 cout << greeting << endl;
return 0;
 }
When the above code is compiled and executed, it produces result something as follows:
Greeting message: Hello
 
7.C++ supports a wide range of functions that manipulate null-terminated strings:

8.#include
#include
using namespace std;
int main ()
{
char str1[10] = "Hello";
char str2[10] = "World";
char str3[10]; int len ;
 // copy str1 into str3 strcpy( str3, str1);
cout << "strcpy( str3, str1) : " << str3 << endl;
// concatenates str1 and str2 strcat( str1, str2);
cout << "strcat( str1, str2): " << str1 << endl;
// total lenghth of str1 after concatenation
len = strlen(str1);
cout << "strlen(str1) : " << len << endl;
return 0;
}
 
9.When the above code is compiled and executed, it produces result something as follows:
strcpy( str3, str1) : Hello
strcat( str1, str2): HelloWorld
strlen(str1) : 10

10.The String Class in C++:
The standard C++ library provides a string class type that supports all the operations mentioned above, additionally much more functionality. We will study this class in C++ Standard Library but for now let us check following example:

At this point you may not understand this example because so far we have not discussed Classes and Objects. So can have a look and proceed until you have understanding on Object Oriented Concepts.