Key Concepts

Review core concepts you need to learn to master this subject

if Statement

if (a == 10) { // Code goes here }

An if statement is used to test an expression for truth.

  • If the condition evaluates to true, then the code within the block is executed; otherwise, it will be skipped.

else Clause

if (a == 10) { // Code goes here }

An else clause can be added to an if statement.

  • If the condition evaluates to true, code in the if part is executed.
  • If the condition evaluates to false, code in the else part is executed.

switch Statement

if (a == 10) { // Code goes here }

A switch statement provides a means of checking an expression against various cases. If there is a match, the code within starts to execute. The break keyword can be used to terminate a case.

default is executed when no case matches.

Relational Operators

if (a == 10) { // Code goes here }

Relational operators are used to compare two values and return true or false depending on the comparison:

  • == equal to

  • != not equal to

  • > greater than

  • < less than

  • >= greater than or equal to

  • <= less than or equal to

else if Statement

if (a == 10) { // Code goes here }

One or more else if statements can be added in between the if and else to provide additional condition(s) to check.

Logical Operators

if (a == 10) { // Code goes here }

Logical operators can be used to combine two different conditions.

  • && requires both to be true (and)
  • || requires either to be true (or)
  • ! negates the result (not)
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Conditionals & Logic
Lesson 1 of 2
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  1. 1
    Every program we’ve seen so far has only had one possible path of execution — they all execute line by line, from top to bottom. And every time you run one of those programs, it gives you the same …
  2. 2
    Before we dive deep into the syntax of the if statement, let’s do a demo! Here, we have coinflip.cpp program that simulates a coin toss: - 50% of the time, it’s Heads. - 50% of the time, i…
  3. 3
    An if statement is used to test an expression for truth and execute some code based on it. Here’s a simple form of the if statement: if (condition) { some code } If the condition is true, …
  4. 4
    When writing conditional statements, sometimes we need to use different types of operators to compare values. These operators are called relational operators. To have a condition, we need relati…
  5. 5
    We can also add an else clause to an if statement to provide code that will only be executed if the condition is false. Here’s a form of an if statement that includes an else clause: if (condition…
  6. 6
    So what happens if you want more than two possible outcomes? This is where else if comes in! if (condition) { some code } else if (condition) { some code } else { some code } The el…
  7. 7
    Now that we know how if, else if, else work, we can write programs that have multiple outcomes. Programs with multiple outcomes are so common that C++ provides a special statement for it… the swi…
  8. 8
    Congratulations! 🙌 Here are some of the major concepts: - An if statement checks a condition and will execute a task if that condition evaluates to true. - if / else statements make binary decisi…
  1. 1
    Often, when we are trying to create a control flow for our program, we’ll encounter situations where the logic cannot be satisfied with a single condition. Logical operators are used to combine …
  2. 2
    The and logical operator is denoted by &&. It returns true if the condition on the left and the condition on the right are both true. Otherwise, it returns false. Here’s the truth table: | a …
  3. 3
    The or logical operator is denoted by ||. It returns true when the condition on the left is true _or_ the condition on the right is true. Only one of them needs to be true. Here’s the truth table…
  4. 4
    The not logical operator is denoted by !. It reverses the bool outcome of the expression that immediately follows. Here’s the truth table: | a | !a | | — | — | | false | true | | true | fals…
  5. 5
    Awesome! In this mini-lesson, we’ve added more operators to our toolbox: - &&: the and logical operator - ||: the or logical operator - !: the not logical operator

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