If-Else Statements in C++

Questions and Answers

What does an if-else statement control in a program?

Memory allocation

User interaction

Data input and output

Conditional branching (correct)

In an if statement, when is the else branch executed?

When an error occurs in the if branch

When the condition evaluates to zero (correct)

When the condition is truthful

When the program is compiled

Which of the following values can evaluate to true in an if condition?

Empty string

Non-null pointer (correct)

Zero

Null pointer

Which syntax is used to initiate an if-else statement?

if (condition) { statements; } else { other_statements; } Signup and view all the answers

In an if-else statement, control will pass to the next statement in the program unless which of the following occurs?

The if-branch or else-branch contains a break, continue, or goto Signup and view all the answers

What type of values can the condition of an if statement not evaluate to?

Any structure Signup and view all the answers

What is an unambiguous conversion in the context of an if-else statement?

Converting a class type directly into an arithmetic or boolean type Signup and view all the answers

Which component of the if-else statement can include an initializer?

The selection-statement Signup and view all the answers

Study Notes

Overview of If-Else Statements in C++

Controls conditional branching based on specified conditions.
Executes statements in the if-branch when conditions evaluate as true (non-zero).
Skips the if-branch when conditions evaluate as false (zero); executes else-branch if present.

Condition Evaluation

Conditions that result in non-zero (true) include:
- Boolean value true.
- Non-null pointer.
- Any non-zero numeric value.
- Class types that can convert to arithmetic, boolean, or pointer types.

Syntax Structure

Initialization Statement:
- Can be an expression statement or a simple declaration.
Condition:
- Can be a plain expression with optional specifications.
Statement:
- May refer to either an expression statement or compound statements.
Expression Statement:
- Consists of an optional expression followed by a semicolon.
Compound Statement:
- Enclosed within braces {} and can contain a sequence of statements.
Branches:
- If-Branch: Statements executed if the condition is true.
- Else-Branch: Statements executed if the condition is false and after an else.

Selection Statement Format

Basic forms:
- if (condition) if-branch
- if (condition) if-branch else else-branch
Introduced optional elements in C++17.

Additional Considerations

The condition can include side effects during evaluation.
Control flow continues to the next statement unless interrupted by break, continue, or goto within the branches.
Else clauses are linked to the nearest preceding if without a matching else.

Example Code Structure

Initial code snippet demonstrates if statements integrating both if- and else-branches:

#include <iostream>
using namespace std;

int main() {
    int x = 10;

    if (x < 11) {
        cout << "x is less than 11";
    }
    // Add additional statements as needed
}

Description

This quiz covers the fundamentals of if-else statements in C++. It explores the syntax, usage, and different types of conditional statements like if with initializer and if constexpr. Test your understanding of how these statements control the flow of your C++ programs.