ITERATING WITH FOR LOOPS

ITERATING WITH FOR LOOPS:
In previous post we understand basic execute anonymous and check the governor limits. The purpose of following example to understand for loop and if conditions

Example 1:
// Use a For loop to go through all the integers between 0 and 6
//  and output the name of the corresponding day of the week.
//  0 = 'Sunday', 1 = 'Monday', etc...
for(Integer dayNumber = 0; dayNumber <=6; dayNumber++){
 if(dayNumber==0){
   System.debug('Sunday');
 } else if(dayNumber==1){
   System.debug('Monday');
 } else if(dayNumber==2){
   System.debug('Tuesday');
 } else if(dayNumber==3){
   System.debug('Wednesday');
 } else if(dayNumber==4){
   System.debug('Thursday');
 } else if(dayNumber==5){
   System.debug('Friday');
 } else if(dayNumber==6){
   System.debug('Saturday');
 }
}

Example 2:
/* Fibonacci Sequence: The first two Fibonacci numbers are 0 and 1 and then the next Fibonacci number is found by adding the previous two together  */

// Setup the initial variables to hold the old number, current number, and fibonacci number
Integer oldNumber = 0;
Integer currentNumber = 1;
Integer fibonacciNumber = 0;

// use a loop to output all the fibonacci numbers between 0 and 100
while (fibonacciNumber < 100) {
     
      System.Debug(fibonacciNumber);  // output the Fibonacci number

      // calculate the next fibonacci number by adding the
      // current number to the old number
      fibonacciNumber= currentNumber + oldNumber;
     
      // now set the new values of the old and current numbers
      oldNumber = currentNumber;
      currentNumber = fibonacciNumber;
}

Example 3: This example shows calculating data with primitives
/* SNIPPET 1 */
Boolean b;
Boolean bIsNull;
if(b == null){
  bIsNull = true;
} else {
  bIsNull = false;
}
System.debug(bIsNull);


/* SNIPPET 2 */
// Declare a string = 'He'
String myString1 = 'He';

// Declare a string = 'llo'
String myString2 = 'llo';

// Add the two strings you declared above together into a variable named s
String s = myString1 + myString2;

Boolean b;
if(s=='hello'){
  b = true;
} else {
  b = false;
}
System.debug(b);


/* SNIPPET 3 */
Integer i = 1;
Integer j = 2;
while(i < 3){
  j=i*j;  // Set j equal to i multiplied by j
  i++;    // Increment the i variable by 1
}
System.debug('The integer j = ' + j);

Execute Anonymous - II

Execute Anonymous :
Continuous to previous post some more examples to understand debugging and governor limits using execute anonymous

List<Contact> contactList = new List<Contact>();
for(Integer i=0; i <= 5; i++){
  for(Integer j=0; j <= 10; j++){
    if(i < j) {
      System.debug('i is less than j');
      Integer k=i;
      while(k < j){
        System.debug('k < j');
        k++;
  }
     } else {
        System.debug('i is not less than j');
     }
  }
 }
-----------------------------------------------------------------------------------------------------
 public class ContactCounter{
  public void countSmithContacts(List<Contact> listOfContacts){
     // the code of the method goes here…
    Integer smithCounter = 0;
     for(Contact c : listOfContacts){
      if(c.lastname=='Smith'){
        smithCounter++;
         System.debug('Smith #' + smithCounter);
  }
     }
  }
 }
------------------------------------------------------------------------------------------------------
String stateAbbreviation = 'IL';
String stateName;
if (stateAbbreviation == 'IL') {
stateName = 'Illinois';
} else if (stateAbbreviation == 'IA') {
stateName = 'Iowa';
} else if (stateAbbreviation == 'CA') {
stateName = 'California';
}
System.debug('State = ' + stateName);

Here is the governor limits info for first example

Execute Anonymous - I

Execute Anonymous :
This is a simple example to understand how we can use apex class for various actions. The reason we are implementing in Execute Anonymous we can see immediate effect on Salesforce server and can see logs for debug statement and my favorite to observe Governor Limits

public class Updater{
  public void updateFirstContact(List<Contact> listOfContacts){
    if(listOfContacts!=null && (!listOfContacts.isEmpty())){
      Contact firstContact = listOfContacts.get(0);
      if(firstContact.id!=null){
        firstContact.firstName += '-updated';
        firstContact.lastName = firstContact.lastName + '-updated';
        Database.update(firstContact);
      }
    } else {
      System.debug('There are no contacts in the list');
    }
  }
}

Account theAccount = new Account(name='My First Account');
insert theAccount;
System.debug('The new Account Id is ' + theAccount.id);

List<Contact> contactList = new List<Contact>();
for(Integer iCounter=0; iCounter <= 5; iCounter++){
  Contact oneContact= new Contact();
  oneContact.accountId=theAccount.id;
  oneContact.firstName='testFirst' + iCounter;
  oneContact.lastName='testLast' + iCounter;
  contactList.add(oneContact);
  System.debug('Added to list contact #' + iCounter);
}
Database.insert(contactList);

Integer howManyContacts= [select count() from Contact where accountId=:theAccount.id];
System.debug('The account has ' + howManyContacts + ' contacts.');

System.debug(contactList.get(0));
updater myUpdater = new updater();
myUpdater.updateFirstContact(contactList);
System.debug(contactList.get(0));

Here is the debug statements screen looks like