Branching and loops are at the heart of most calculations and decisions in your program.

Normally code is executed top to bottom. A number of keywords change this:

(For branching)
- if
- else
(For looping)
- while
- for

These keywords work with conditions that are logical expressions that can be true or false

(x > 0)
(y - 2 < b)

Here, parenthesis or round brackets are necessary around conditions in C++.

Operators

There are operators to compare two operands -

> >= < <= == !=

Note:
==: two equal signs are used for comparison
=: single equal sign in used for assignment
!: means 'not'

if

condition must always have ()
statements will run only if condition is true

Code to compare two numbers

Garbage In, Garbage Out

Type rules apply here as well. Giving decimal value confuses the parser and secondNumber is assigned value 0.

else

an else can only be used right after an if
here else statements run if condition is false, i.e. i >= j.

while

keeps going as long as the condition is true
curly braces are optional for single line statements but use them anyway
a while loop may not run at all if the condition is never true
loop body must change something about the condition, otherwise we may have an infinite loop

Comparing two numbers until user says otherwise

Garbage In, Garbage Out

for

Traditional for loop has three parts separated by semi-colons (not commas) -

initialiser (typically also declares the variable)
continue condition
incrementer

Loop body doesn't have to change anything about the condition if the incrementer does.

Tip: Use a debugger to see which statement in executed.

TO-DO: Write a "Guess the Number" game where you hard code a number into code and then prompt user to guess the number. If the guessed number is lesser/greater than the hard coded number, let the user know. If the user guess correctly, prompt success response and exit.

Code for reference.