C++ video notes

Question 1

include <iostream> what does this do</iostream>

Answer 1

This includes the standard library in C++, and allows you to print out stuff or get input from the user using “std::”

Question 2

What does std::cout stand for?

Answer 2

It means character out.
Ex: std::cout &laquo_space;“Hello World!”;

Question 3

Why do you have to do return 0; for the main function?

Answer 3

It has an “int” return type

Question 4

What is cout?

Answer 4

It’s an object that belongs to the std namespace. For example, std::cout &laquo_space;“Hello World!”;

Question 5

How to have a constant value as your variable name?

Answer 5

You do const int value1 = 0; //still have to specify the data type

Question 6

How to print out strings and variables on the same line?

Answer 6

you would first have to declare a variable, and then use the &laquo_space;to combine the two. For example

int value1 = 20;

std::cout &laquo_space;“x = “ &laquo_space;value1;

if you want a newline, you would do

std::cout &laquo_space;“x = “ &laquo_space;value1 &laquo_space;“\n”;

OR, you can do this (which is actually preferred)

std::cout &laquo_space;“x = “ &laquo_space;value1 &laquo_space;std::endl;

so it’s the same role as \n and you also use &laquo_space;in this scenario to add a newnline after your value or whatever (ykwim)

Question 7

What is the way to not use std:: in your code to make it look cleaner (just include the object names)

Answer 7

you would do above your main function, “using namespace std;”

Question 8

What is the insertion operator in C++?

Answer 8

It’s “«”

Question 9

What is the benefit with cout combined with std::cin?

Answer 9

With cout, you can also get input from the user by printing out a statement and then declaring a value for the user to input. Then, with std::cin, you can get that user input, and store it in the variable

example:

std::cout &laquo_space;“Enter a value: “ &laquo_space;std::endl;
int value1;
std::cin&raquo_space; value1;

//this doesn’t print out the value, but instead stores it in the variable value1

Question 10

How to memorize which way the &laquo_space;goes?

Answer 10

For cout, it is going inward because you are getting user info, whereas for cin, it is going the other way because you are storing that information in a variable
Ex:
std::cout &laquo_space;“Enter the value here: “ &laquo_space;std::endl;
int value1;
std::cin&raquo_space; value1;

Question 11

Tip: When you get a value from the user(like user input), you can’t adjust that value

Answer 11

For example:

std::cout &laquo_space;“Enter a value: “;
int value1;
std::cin&raquo_space; value1 * 30;
you cannot do this for the cin, as cin is used for storing variables, and this is a mathematical expression

Question 12

In the main function, what is the purpose of return 0;

Answer 12

It indicates when the program is done running

Question 13

Static type checking

Answer 13

This is when the integers and parameters data types are checked, and sees whether it’s matching before the main function runs.

Question 14

What does the signature of a function mean?

Answer 14

It is the line before the code of a functions which is surrounded by brackets, and includes the return type, the parameters, and the name of the function

For example,
void function_name (int value, double value2){
// insert all the code here, newline is the other direction btw
}

Question 15

How do you avoid typing std:: before every object name?

Answer 15

Below you including the preprocessor directive, you would do (without the hash) using namespace std;

for example
#include <iostream>
using namespace std;</iostream>

Question 16

True or false, can you define a function signature without having the actual code and declarations?

Answer 16

Yes, then later onwards you can include the signature AND the code for that function, it will still work as normal

Question 17

How to use your function?

Answer 17

you just type the name of the function and then put the value as the parameter(inside of the paranthesis)

Question 18

What does #include <string> do in c++?</string>

Answer 18

It allows you to include string variables, unlike in C where you can declare arrays as strings, like char arrays

Question 19

class in C++

Answer 19

This contains attributes of that specific class name and you can create objects of that class

For example,

class BankAccount{
int balance;
string name;
};

These attributes are key for what defines a bank account

Question 20

How do you create a variable for this class and define the attribute values from that class?

Answer 20

You would have to use the period, for example

BankAccount value1;
value1.balance = …;
value1.name = …;

std::cout &laquo_space;value1.name &laquo_space;“has $” &laquo_space;value1.balance &laquo_space;std::endl;

Question 21

It’s just good practice to include endl.

Answer 21

OKAY

Question 22

Review how to implement functions into classes

Answer 22

OKAY

Question 23

What are the six phases of C++ development environment?

Answer 23

The first phase is edit, which is basically writing the code and putting it into an editor in proper format
The second phase is preprocessor, this is what is run at first, and is executed automatically before compiling

Ex: #include <iostream>
The third phase is the compile phase, and this is when the actual code starts to be put into code that the machine can understand</iostream>

The fourth phase is the link phase, which is used to link what you have as the preprocessor directive (ex: #include <iostream>) and also the functions and objects from that namespace in order for your code to work properly</iostream>

The fifth phase is when the computer uses RAM(it takes stuff from the hard drive and uses it’s computer memory to finally execute the code)

Review the fifth and sixth phase

Question 24

How to define a namespace in C++?

Answer 24

A namespace allows you to have the same variable names across different name namespaces to avoid confusion, as you can just do different_namespace …

an example of a namespace is std, as you can see, we use std by including two colons after std

When we create a namespace, we can put namespace::attribute or whatever variable or function or object is found within that namespace

Declaration of namespace:
namespace hello{
int value1;
}

int main() {
std::count &laquo_space;hello::value1;
return 0;
}

Question 25

if, else statements are what you would see normally in C, like if (string1 == string2){
return …;
}

Answer 25

ok

Question 26

For loops, while loops, and do while loops are also the same as C for the most part

Answer 26

Okay

Question 27

What is the difference between the size and sizeof function in C++?

Answer 27

value.sizeof(int) or whatever data type(float, double, string, long) gets the size of the data type and puts it in an integer value, whereas .size() which is next to a variable name of a string gets the length of the string

Question 28

Review how strings aren’t good with bounds checking

Answer 28

Ok

Question 29

What are the three parts of cin from the std namespace?

Answer 29

Reading the value:
The user types in the input and hits enter to end the input
Transmit:
Enter indicates your machine to make your input into a buffer
Store:
Inspects the variable type and stores it into the variable

Question 30

How to store multiple values using cin in C++?

Answer 30

You would do

using namespace std;
int value1;
int value2;

cout &laquo_space;“Enter 2 values of integer here: “ &laquo_space; endl;
cin&raquo_space; value1&raquo_space; value2;

Question 31

How does cin reading work for multiple values?

Answer 31

It basically notices whether there is a space between the two values, and in that place where there are spaces, it is called a skip delimeter and moves on to the next value or the next data type

Also, newline is also considered a delimeter

Question 32

What happens if instead of spaces that are seperated out, the user puts enter, enter and enter

Answer 32

Instead of spaces, it is actually considered a newline (not only endl or \n is considered a newline)

Question 33

How to create a struct in C++ (and how is it different from a class, review how it is different ion really get that)

Answer 33

you create a struct by doing this:

struct Name{
int value;
string value1;
};

and then you can create a struct variable by doing this

Name variable;
variable.value;
variable.value1;

and you can set those attributes to actual values, also struct automatically have public attributes unlike classes

Question 34

What if you don’t do #include <string> at the top, how can you define a string?</string>

Answer 34

You can do std::string variableName = “…”;