// * Control Flow statements: Used to control the flow of code execution. You can skip a block of code or have a block of code executed repeatedly. These statements include: if-else (conditional) statements, switch statements and loops

// * if - else / Conditional Statements

if(<Boolean>) {

} else {

}

// * if Statement
Integer num = 10;
System.debug('Start...');
if(num > 50) {
    System.debug('num is greater than 50');
}
System.debug('End...');

// * if Statement with else
Integer num = 100;
System.debug('Start...');
if(num > 50) {
    System.debug('num is greater than 50');
    System.debug('num is greater than 50');
    System.debug('num is greater than 50');
} else {
    System.debug('num is not greater than 50 and is: ' + num);
    System.debug('num is not greater than 50 and is: ' + num);
    System.debug('num is not greater than 50 and is: ' + num);
}
System.debug('End...');

// * Repeated if else statements, if else chaining
Integer num = 50;
System.debug('Start...');
if(num > 50) {
    System.debug('num is greater than 50');
} else if(num < 50) {
    System.debug('num is less than 50');
} else if(num == 50) {
    System.debug('num is equal to 50');
} else {
    System.debug('num is null');
}
System.debug('End...');

// * nested if else
enum SalesforceRelease {
    SPRING,
    SUMMER,
    WINTER
}

Integer age = 10;
SalesforceRelease currentRelease = SalesforceRelease.WINTER;

if(currentRelease == SalesforceRelease.SPRING) {
    if(age >= 18) {
        System.debug('Richard will drive a bike.');
    } else {
        System.debug('Richard will board a bus.');
    }
} else if(currentRelease == SalesforceRelease.SUMMER) {
    if(age >= 18) {
        System.debug('Richard will drive a car.');
    } else {
        System.debug('Richard will board a metro.');
    }
} else if(currentRelease == SalesforceRelease.WINTER) {
    if(age >= 18) {
        System.debug('Richard will drive a truck.');
    } else {
        System.debug('Richard will stay home.');
    }
}

// * Switch Statements

switch on expression { // * Value can be Integer, Long, sObject, String (case sensitive) or Enum
    when value1 {

    }
    when value2 {

    }
    when else {

    }
}

Integer i = 20;
switch on i {
    when 1 {
        System.debug('i is 1');
    }
    when 2 {
        System.debug('i is 2');
    }
    when null {
        System.debug('i is null');
    }
    when else {
        System.debug('i is none of these');
    }
}

enum SalesforceRelease {
    SPRING,
    SUMMER,
    WINTER,
    AUTUMN
}

SalesforceRelease currentRelease = SalesforceRelease.AUTUMN;

switch on currentRelease {
    when SPRING, SUMMER {
        System.debug('Richard will ride a bike');
    }
    when WINTER {
        System.debug('Richard will drive a car');
    }
    when null {
        System.debug('Richard will do nothing');
    }
    when else {
        System.debug('Richard will stay at home');
    }
}

// * Loops

// * While loop

while(condition) {
    // * Code
}

Integer i = 100;
while(i<11) {
    System.debug('Value of i = ' + i);
    i++;
}

Integer i = 1;
while(i<6) { // * Infinite loop
    System.debug('Value of i = ' + i);
}

// * Do while loop

do {
    // * Code
} while(condition);

Integer i=100;
do {
    System.debug('Value of i = ' + i);
    i++;
} while(i<11);

List<Integer> numbers = new List<Integer>();
numbers.add(1);
numbers.add(2);
numbers.add(3);
numbers.add(4);
numbers.add(5);
numbers.add(6);
numbers.add(7);
numbers.add(8);
numbers.add(9);
numbers.add(10);
System.debug(numbers);

List<Integer> numbers = new List<Integer>();
Integer i = 1;
while(i<101) {
    numbers.add(i);
    i++;
}
System.debug(numbers);
System.debug(numbers.size());

// * For Loop

// * Traditional for loop
for(initialization; condition; operation) {
    // * Code
}

for(Integer i=1; i<6; i++) {
    System.debug('Value of i = ' + i);
}

for(Integer i=1, j=0; i<6; i++) {
    System.debug('Value of i = ' + i + ' & j = ' + j);
}

// * List/Set iteration for loop
for(variable : <list or set>) {
    // * Code
}

Set<Integer> numbers = new Set<Integer>{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
for(Integer num : numbers) {
    if(num==5) {
        // break;
        continue;
    }
    System.debug('Current element of set = ' + num);
}

// * Adding/Removing elements while iterating a collection is not allowed

// * Break and Continue keywords