Decision Making

In making decisions in programming, the programmer should use comparison expression and then choose a path in which to take depending on the answer to the comparison.

Comparison Operators

Comparison operators are used to compare two values which then results to a boolean value. Here are some of the comparison operators in C++:

Operator	Name	Example	Result
`==`	Equal to	`25 == 25`	`true`
`!=`	Not equal to	`25 != 30`	`true`
`<`	Less than	`25 < 30`	`true`
`<=`	Less than or equal to	`25 <= 30`	`true`
`>`	Greater than	`30 > 25`	`true`
`>=`	Greater than or equal to	`30 >= 25`	`true`

Logical Operators

Logical operators are used to combine two or more comparison expressions. Here are some of the logical operators in C++:

Operator	Name	Example	Result
`&&`	AND	`25 < 30 && 5 < 10`	`true`
`\|\|`	OR	`(25 < 30) \|\| (5 > 10)`	`true`
`!`	NOT	`!(25 < 30)`	`false`

Decision Making Statements

Decision making statements are used to make decisions in a program. Here are some of the decision making statements in C++:

`if` Statement

The if statement is used to execute a block of code only if the condition is true. Here is the syntax of the if statement:

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

Here is an example of using the if statement:

int age = 25;

if (age >= 18) {
    cout << "You are an adult";
}

`if-else` Statement

The if-else statement is used to execute a block of code if the condition is true and another block of code if the condition is false. Here is the syntax of the if-else statement:

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

Here is an example of using the if-else statement:

int age = 15;

if (age >= 18) {
    cout << "You are an adult";
} else {
    cout << "You are a minor";
}

nested `if-else` Statement

The nested if-else statement is used to execute a block of code if the condition is true and another block of code if the condition is false. Here is the syntax of the nested if-else statement:

if (condition1) {
    // code to be executed if condition1 is true
} else if (condition2) {
    // code to be executed if condition2 is true
} else {
    // code to be executed if both condition1 and condition2 are false
}

Here is an example of using the nested if-else statement:

int age = 15;

if (age >= 18) {
    cout << "You are an adult";
} else if (age >= 13) {
    cout << "You are a teenager";
} else {
    cout << "You are a child";
}

`switch` Statement

The switch statement is used to execute a block of code based on the value of a variable. It is a more efficient way to write multiple if-else statements. Here is the syntax of the switch statement:

switch (variable) {
    case value1:
        // code to be executed if variable is equal to value1
        break;
    case value2:
        // code to be executed if variable is equal to value2
        break;
    default:
        // code to be executed if variable is not equal to any of the values
}

Here is an example of using the switch statement:

int day = 3;

switch (day) {
    case 1:
        cout << "Monday";
        break;
    case 2:
        cout << "Tuesday";
        break;
    case 3:
        cout << "Wednesday";
        break;
    default:
        cout << "Invalid day";
}

Tenary Operator

The tenary operator is a shorthand way of writing an if-else statement. Here is the syntax of the tenary operator:

(condition) ? expression1 : expression2;

Here is an example of using the tenary operator:

int age = 15;

string result = (age >= 18) ? "You are an adult" : "You are a minor";

cout << result;

In the example above, the value of result will be "You are a minor" because the condition age >= 18 is false.