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C++ `Strings`

C++ provides two types of string representations:

C-style strings
The string class type introduced by C++

C-style Strings

C-style strings originate from the C language and continue to be supported in C++. A string is essentially a one-dimensional array of characters terminated by a null character \0. Therefore, a null-terminated string contains the characters that comprise the string followed by the null character.

The following declaration and initialization create a string tutorialpro. Since a null character is stored at the end of the array, the size of the character array is one more than the number of characters in the word tutorialpro.

char site[7] = {'R', 'U', 'N', 'O', 'O', 'B', '\0'};

According to the rules of array initialization, you can write the above statement as:

char site[] = "tutorialpro";

The following is the memory representation of a string defined in C/C++:

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

Example

#include <iostream>

using namespace std;

int main ()
{
   char site[7] = {'R', 'U', 'N', 'O', 'O', 'B', '\0'};

   cout << "tutorialpro.org: ";
   cout << site << endl;

   return 0;
}

When the above code is compiled and executed, it produces the following result:

tutorialpro.org: tutorialpro

C++ has a large set of functions for manipulating null-terminated strings:

No.	Function & Purpose
1	strcpy(s1, s2); <br>Copies string s2 into string s1.
2	strcat(s1, s2); <br>Concatenates string s2 to the end of string s1. Concatenation can also be done with the + operator, for example: <br> string str1 = "tutorialpro";<br>string str2 = "google";<br>string str = str1 + str2;
3	strlen(s1); <br>Returns the length of string s1.
4	strcmp(s1, s2); <br>Returns 0 if s1 and s2 are the same; less than 0 if s1<s2; greater than 0 if s1>s2.
5	strchr(s1, ch); <br>Returns a pointer to the first occurrence of character ch in string s1.
6	strstr(s1, s2); <br>Returns a pointer to the first occurrence of string s2 in string s1.

The following example uses some of these functions:

Example

#include <iostream>
#include <cstring>

using namespace std;

int main ()
{
   char str1[13] = "tutorialpro";
   char str2[13] = "google";
   char str3[13];
   int  len ;

   // Copy str1 into str3
   strcpy( str3, str1);
   cout << "strcpy( str3, str1) : " << str3 << endl;

   // Concatenate str1 and str2
   strcat( str1, str2);
   cout << "strcat( str1, str2): " << str1 << endl;

   // Total length of str1 after concatenation
   len = strlen(str1);
   cout << "strlen(str1) : " << len << endl;

   return 0;
}

When the above code is compiled and executed, it produces the following result:

strcpy( str3, str1) : tutorialpro
strcat( str1, str2): tutorialprogoogle
strlen(str1) : 12

String Class in C++

The C++ Standard Library provides a string class type that supports all the operations mentioned above, and more. We will learn about the C++ Standard Library string class in this chapter. For now, let's look at the following example:

#include <iostream>
#include <string>

using namespace std;

int main ()
{
   string str1 = "tutorialpro";
   string str2 = "google";
   string str3;
   int  len ;

   // Copy str1 into str3
   str3 = str1;
   cout << "str3 : " << str3 << endl;

   // Concatenate str1 and str2
   str3 = str1 + str2;
   cout << "str1 + str2 : " << str3 << endl;

   // Total length of str3 after concatenation
   len = str3.size();
   cout << "str3.size() :  " << len << endl;

   return 0;
}

When the above code is compiled and executed, it produces the following result:

str3 : tutorialpro
str1 + str2 : tutorialprogoogle
str3.size() :  12

You might not fully understand this example yet, as we haven't discussed classes and objects so far. For now, you can just take a rough look at this example and come back to it after understanding the concepts of object-oriented programming.

Example

#include <iostream>
#include <string>

using namespace std;

int main ()
{
   string str1 = "tutorialpro";
   string str2 = "google";
   string str3;
   int  len ;

   // Copy str1 to str3
   str3 = str1;
   cout << "str3 : " << str3 << endl;

   // Concatenate str1 and str2
   str3 = str1 + str2;
   cout << "str1 + str2 : " << str3 << endl;

   // Total length of str3 after concatenation
   len = str3.size();
   cout << "str3.size() :  " << len << endl;

   return 0;
}

When the above code is compiled and executed, it produces the following result:

str3 : tutorialpro
str1 + str2 : tutorialprogoogle
str3.size() :  12

❮ Cpp Functions Cpp Examples Monkey Eating Peach ❯

C++ Strings

C-style Strings

Example

Example

String Class in C++

Example

C++ `Strings`