C++ Day 8

 Great! On ** day 8 ** of a specific C ++ course, you will usually go into one of these main subjects:

,

## ✅ ** string in C ++ **

Strings are sequence of characters. C ++ provides two main methods of working with them:

1. ** C-style strings ** (character arrays)
2. ** c ++ 'string' class ** (from standard library)

We will focus on both.

,

### 🔹 1. ** C-style strings (character arrays) **

`` `CPP
#INCLUDE <iostream>
#INCLUDE <CSTRING>
using namespace std;

int main() {
Four names [20];

Cout << "Enter your name:";
Cin >> Name;

Cout << "Hello," << Name << "!" << Endl;

Return 0;
,
,

#### Useful C-Style String Functions' <cstring> `:

* `Strlen () - String length
* `Strcpy ()` - Copy Strings
* 'Strcat () ` - Constenate
* 'Strcmp () ` - Compare

`` `CPP
Char Str1 [] = "Hello";
char str2 [] = "world";

Cout << Strcat (Str1, Str2); // Hello World
,

,

### 🔹 2. ** c ++ string class **

Simple and safe to use:

`` `CPP
#INCLUDE <iostream>
#INCLUDE <String>
using namespace std;

int main() {
String name;

Cout << "Enter your name:";
Getline (cin, name); // Accepts the entire line including spaces

Cout << "Welcome," << Name << "!" << Endl;

Return 0;
,
,

#### with general operation 'string':

`` `CPP
String S = "Hello";
cout << s.length (); // 5
s += "world"; // Concatenate
cout << s.substr (0, 5); // "hello"
cout << S.find ("low"); // 3
,

,

### 📝 practice problems

1. Calculate the number of vowels in a string.
2. Check if a string is a ** palindrome **.
3. Opposite a string.
4. Compare two wires without using `==`.
5. Count words in a sentence.

,

### 🔄 Example: Check Palindrome

`` `CPP
Bool ispalindrome (string s) {
Int start = 0, end = s.length () - 1;
While (beginning <end) {
If (s [start]! = s [end])