If-Else Statements in C++

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
  }
  

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.