Mastering C++ Conditions: Logic and Decision-Making in Programming - w9school

C++ If ... Else

Conditional Statements in C++

C++ is an all-purpose programming language designed for use across many environments, using text editors for writing code and compilers for compiling it into executable programs that your computer understands. There are several compiler options available such as Microsoft Visual Studio; there are also free open source options for Linux and Apple operating systems.

C++ offers several conditional statements, with the if statement being the most basic one. This statement checks whether a block of statements will be executed or not according to a boolean value; if true, statements within the curly brackets are executed, otherwise false and they're ignored.

The if-else statement is another conditional statement which allows multiple conditions to be checked simultaneously, like an if statement. However, unlike an if statement, all conditions within curly braces must be valid at once in order for this one to work effectively.

Switch statements allow you to check multiple cases for one variable at once. They work similarly to an if-else ladder, except they evaluate your expression only once and compare it against all of its values; if an expression matches any one of them then that case's statement will be executed, otherwise the switch statement is ignored and your program continues running normally.

C++ Conditions and If Statements

You've already heard the fact that C++ supports the common logical requirements that come from math:

• More than: a less than: a
• less that or more than A= b
• More than A > B
• greater than A > b
• Equal to a == b
• Not equal to Not Equal to: a! = b!

You can make use of these conditions to carry out different actions in different scenarios.

C++ has the following conditional statements:

• Use the if to define a block of code that will be executed when a specific circumstance is true
• Utilize another to define an element of code that needs to execute in the event that the conditions are false.
• Use alternatively you need to create the new requirement to check, in the event that the first condition fails.
• Use the switches to indicate a variety of alternative blocks of code that will be executed

The if Statement

Utilize to use the If statement to define the block that contains C++ code to be executed if a particular condition exists. the case.

Syntax

if (condition) {
  // block of code to be executed if the condition is true
}

Take note that the word "if" is written in lowercase letters. Lowercase characters (If or If) could result in an error.

In the following example we will test two numbers to determine if 20 is greater than. If true Print a text:

Example

if (20 > 18) {
  cout << "20 is greater than 18";
}

It is also possible to test the following variables:

Example

int x = 20;
int y = 18;
if (x > y) {
  cout << "x is greater than y";
}

Example explained

In the above example, we will use two factors, x and y to determine if there is a greater value than y for x (using the > operator). Since x is 20 and 18 is y and we are aware that 20 is higher than 18 we write on the screen that "x is greater than y".

C++ Else

The else Statement

Make use of the else statement to define an element of code to be executed when it is False.

Syntax

if (condition) {
  // block of code to be executed if the condition is true
} else {
  // block of code to be executed if the condition is false
}

Example

int time = 20;
if (time < 18) {
  cout << "Good day.";
} else {
  cout << "Good evening.";
}
// Outputs "Good evening."

Example explained

In the above example in the above example, the it is clear that the time (20) is more than 18, which means it is incorrect. In this case, we can proceed towards an otherwise situation and then print on the monitor "Good evening". In the event that time is lower than 18 hours, the program will output "Good day".

C++ Else If

The else if Statement

Make use of the else If statement to indicate an additional condition in the event that the previous conditions are not true.

Syntax

if (condition1) {
  // block of code to be executed if condition1 is true
} else if (condition2) {
  // block of code to be executed if the condition1 is false and condition2 is true
} else {
  // block of code to be executed if the condition1 is false and condition2 is false
}

Example

int time = 22;
if (time < 10) {
  cout << "Good morning.";
} else if (time < 20) {
  cout << "Good day.";
} else {
  cout << "Good evening.";
}
// Outputs "Good evening."

Example explained

In the above example it is clear that the it is clear that the time (22) is higher than 10, which means it is clear that the second conditions is not true. The second condition, which is in the else if condition, is also false, and we proceed to the condition for else since condition 1 and condition 2 are both false. Print on the display "Good evening".

If, however, it was the day of 14, the program will write "Good day."

C++ Short Hand If Else

Short Hand If...Else (Ternary Operator)

Additionally, there is a shorthand If else, also called"the the ternary operator due to its three operands. It is a way to replace several lines of code in one line. It is commonly employed to substitute simple statements like:

Syntax

variable = (condition) ? expressionTrue : expressionFalse;

In lieu of writing:

Example

int time = 20;
if (time < 18) {
  cout << "Good day.";
} else {
  cout << "Good evening.";
}

It is easy to write:

Example

int time = 20;
string result = (time < 18) ? "Good day." : "Good evening.";
cout << result;

Conclusion

C++ conditions are statements used to decide whether a block of code will run in a program. There are various forms of conditional statements, but perhaps the most widely-used decision-making statement is an if-else statement which checks a condition and executes either one of two blocks of code depending on its result.

The if-else statement is an indispensable component of any program. As C++'s most basic form of conditional statements, it enables programmers to check a variety of conditions quickly. You can use multiple or single if-else statements simultaneously; alternatively you may use nested versions.

An If-Else statement requires a boolean value to evaluate its condition, which could be an expression, variable, or function call. The value must evaluate to either true or false for proper evaluation; otherwise it will be disregarded and the statement ignored.

An if-else statement allows one or both blocks of code to execute, with either block being evaluated depending on whether or not its counterpart executes; if both execute simultaneously, only the second will be evaluated; otherwise both blocks will be disregarded. It can also be combined with another if-then-else statement to evaluate multiple conditions simultaneously.

Use a while loop to repeat code until its test condition has been fulfilled, as shown here. In this instance, the while loop will repeat until i is equal to 9. This will display Hello there! on screen 10 times before stopping when its condition has been fulfilled and printing it once more.