C++ Part 31

String.Length

//Demonstrates using a string object as if it were an array. #include <iostream> #include <string> using namespace std; int main( ) {    string firstName, lastName;    cout << "Enter your first and last name:\n";    cin >> firstName >> lastName;    cout << "Your last name is spelled:\n";    int i;    for (i = 0; i < lastName.length( ); i++)    {        cout << lastName[i] << " "; // Printing the last name with a space after that.        lastName[i] = '-'; // Replacing the LastName with a "-" character. You not see the result yet.    }    cout << endl;    for (i = 0; i < lastName.length( ); i++)        cout << lastName[i] << " "; //Places a "-" under each letter, and prints a space after theme.    cout << endl;    cout << "Good day " << firstName <<"."<< endl;    return 0; }

C++ Part 30

String | Getline and Cin

string s1, s2;
cin >> s1;
cin >> s2;
If the user types in
I love NavidPlus website.
s1 will receive value "I" and s2 will receive the value "love".
If you want your program to read an entire line of input into a variable of type string , you can use the function getline.
Example:
string line;
cout << "Enter a line of input:\n"; getline(cin, line); cout << line << "END OF OUTPUT\n";

---

I/O with string Objects
You can use the insertion operator << with cout to output string objects. You can input a string with the extraction operator >> and cin.

When using >> for input, the code reads in a string delimited with whitespace.
You can use the function getline to input an entire line of text into a string object.
EXAMPLES
string greeting("Hello"), response, nextLine;
cout << greeting; cin >> response;
getline(cin, nextLine);

C++ Part 29

C++ Strings Part II

If you didn't read the first part, you can find it here.
getline: may input spaces, as before.
e.g., getline(cin,s1) would assign “Navid Plus” to s1 in the "Navid Plus" example.
Example :

#include <iostream>// Coded by https://NavidPlus.blogspot.com#include <string> #include<cstdlib> using namespace std; int main ( ) {     string backString;     cout << "What ever your going to write here, I will reverse it. " <<endl;     getline (cin,backString);     int theIndex = backString.length()-1;     while ( theIndex >= 0)     {        cout << backString [theIndex] ;        theIndex --;     }     cout << '\n' ; }

C++ Part 28

Strings

A char literal is indicated with single quotes (e.g., ’c’), while a string literal is indicated with double quotes (e.g., “abc”).
These are C++ strings and are in library:

• =: Assignment
• <,> , <=, >= ,== , ! =, . . .:
• s[i]: Indexing, i.e., i’th character of s (i ≥ 0)
•  Ex: string s = ‘‘cat’’; char c = s[2] sets c to ’t’
•  + :  Concatenation (overloaded for characters)
• Ex: ‘‘apple’’ + ‘‘pear’’ evaluates to “applepear” while ‘‘apple’’+’s’ evaluates to “apples”
• s.empty(): true if s is an empty string 
• s.length(): length of s (≥ 0) 

//Assignment and comparison operators work for strings but NOT
for all C++ data types.

<<, >> : input/output (still uses whitespace as delimiter).
e.g., cin >> s1 >> s2 would assign “Navid” to s1 and “Plus” to s2,
if the user typed “Navid Plus”.

C++ Part 25

Functions

• Breaks code down into manageable chunks to write (and divide across development team)
• Easier to debug – only one idea behind each module
• Easier to maintain – buggy modules may be replaced without worrying about ramifications on other modules
• Outsiders only need to know a module’s interface, not the details of its implementation.
• Avoids duplication of code ⇒ more compact, and also easier to modify if code has bug  

• Predefined functions: e.g., String.length(): String → Int  
• Programmer-Defined functions: used similarly to predefined functions  
  
  This predefined functions need using namespace std;
  

Source : Absolute C++

C++ Part 24

Working with String - File - While Loop

//NavidPlus.blogspot.com #include <iostream> #include <fstream> #include <string> using namespace std; int main( ) {    string text;   fstream inputStream;    inputStream.open("Website");    while (inputStream >> text) { cout << text << endl; }    inputStream.close();    return 0; } // This Program will read all the input while the condition still true.

Input File : Webiste NavidPlus https://NavidPlus.blogspot.com NavidPlus@Blogger Navid Plus is a Tech blog which is focusing on a Science material that I'll be learned every day through my College and job. Most likely blog's posts contain Programming, Security, Networking, Math, and photography. It is a FUN blog. C Plus Plus @ NavidPlus INTRO Intro to C++ Part 1 Intro to C++ Part 2 Intro to C++ Part 3 Intro to C++ Part 4 Intro to C++ Part 5 Intro to C++ Part 6 Intro to C++ Part 7 Intro to C++ Part 8 _________________________________ C++ By NavidPlus.BlogSpot.Com

If you run this Program, you will find the problem !?

C++ Part 23

Using Getline

Reading From a Text File Using ifstream:

To read from a text file we need to include the fstream library and create an ifstream object which is placed in the std namespace.

#include <fstream> using namespace std;

Example

//NavidPlus.blogspot.com #include <iostream> #include <fstream> #include <string> using namespace std; int main( ) {    string Name, Website;    string description;    fstream inputStream;    inputStream.open("Website");    inputStream >> Name >> Website;    inputStream >> description;    cout << "Name: " << Name << "      "  << "Website: " << Website << endl;    cout << "description: " << description << endl;    inputStream.close();    return 0; }

The input file is Website and must be in the same folder

NavidPlus https://NavidPlus.blogspot.com NavidPlus@Blogger