Strings in C++ Programming

What is a String in C++ ?

A string in C++ is an array of characters terminated by a null character ('\0'). Strings are used to store text, and they are a fundamental data type in C++ programming. Strings in C++ are represented using the char data type.

  • String Declaration: Strings are declared using an array of char elements. For example: char str[20];
  • String Initialization: You can initialize a string by directly assigning it with a string literal: char str[] = "Hello";

Algorithm :-
  • Step 1: Start
  • Step 2: Initialize the string str with "Hello".
  • Step 3: Print the string using ("%s", str).
  • Step 4: Display the output: "Hello".
  • Step 5: Return 0 to indicate successful execution.
  • Step 6: End the program.
  • Step 7: Stop

    • Example 1: Declaring and Initializing a String

    Definition: In this example, we declare a string and initialize it with a string literal.

    This example demonstrates how to declare a string and assign a value to it.

    Expected Behavior: The program stores the string "Hello" in the array str.

    #include <iostream>

int main() {
char str[] = "Hello";
std::cout << str;  // Print the string
return 0;
}

    Algorithm :-
  • Step 1: Start
  • Step 2: Initialize str1 with "Hello, ".
  • Step 3: Initialize str2 with "World!".
  • Step 4: Use str1 += str2 to concatenate str2 to str1.
  • Step 5: Print the concatenated string using std::cout << str1.
  • Step 6: Display the output: "Hello, World!".
  • Step 7: Stop

    • Example 2: Manipulating Strings in C++

    Definition: Strings in C++ can be manipulated using the standard string class, which provides built-in operations for string manipulation.

    This example demonstrates string concatenation using the C++ string class.

    Expected Behavior: The program will concatenate two strings and print the resulting string.

    #include <iostream>
#include <string>

int main() {
std::string str1 = "Hello, ";
std::string str2 = "World!";

str1 += str2;  // Concatenate str2 to str1
std::cout << str1;  // Print the concatenated string
return 0;
}

    Algorithm :-
  • Step 1: Start
  • Step 2: Initialize the string str with "Hello".
  • Step 3: Calculate the length of the string using str.length() and store it.
  • Step 4: Print the length of the string using cout << "Length of string: " << str.length().
  • Step 5: Display the output: "Length of string: 5".
  • Step 6: Return 0 to indicate successful execution.
  • Step 7: Stop

    • Example 3: Finding the Length of a String

    Definition: The length() member function is used to determine the length of a string in C++.

    This example demonstrates how to use length() to find the length of a string.

    Expected Behavior: The program will print the length of the string "Hello".

    #include <iostream>
#include <string>

int main() {
std::string str = "Hello";

std::cout << "Length of string: " << str.length();  // Print the length of the string
return 0;
}

    Algorithm :-
  • Step 1: Start
  • Step 2: Initialize str1 with "Hello" and str2 with "World".
  • Step 3: Compare str1 and str2 using compare().
  • Step 4: If they are equal, print "Strings are equal".
  • Step 5: If they are not equal, print "Strings are not equal".
  • Step 6: Display the appropriate message based on the comparison result.
  • Step 7: Stop

    • Example 4: Comparing Strings

    Definition: The compare() member function is used to compare two strings lexicographically in C++. It returns 0 if the strings are equal, a positive value if the first string is greater, and a negative value if the second string is greater.

    This example demonstrates how to compare two strings using compare().

    Expected Behavior: The program will compare two strings and print whether they are equal or which one is lexicographically greater.

    #include <iostream>
#include <string>

int main() {
std::string str1 = "Hello";
std::string str2 = "World";

if (str1.compare(str2) == 0) {
std::cout << "Strings are equal";
} else {
std::cout << "Strings are not equal";
}

return 0;
}