C Programming Decision Making

Decision Making in C

• Decision making is crucial in programming, guiding the flow of execution based on conditions.
• Common C decision-making statements include: if, if-else, nested if, if-else-if ladder, and switch statements.
• Jump statements such as break, continue, goto, and return control the program flow during decision-making.

If Statement

• The simplest decision-making statement.
• Executes a block of code if a specified condition is true.
• Syntax:

  if(condition) {
      // Statements
  }
  

• Without curly braces, the first statement after if is considered the block’s content.

If-Else Statement

• Extends if statement functionality by allowing an alternative block if the condition is false.
• Syntax:

  if(condition) {
      // Executes if condition is true
  } else {
      // Executes if condition is false
  }
  

Nested If Statements

• Allows placing an if statement inside another if statement for more complex conditions.
• Useful for evaluating multiple conditions sequentially.
• Syntax:

  if(condition1) {
      if(condition2) {
          // Executes if both conditions are true
      }
  }
  

If-Else-If Ladder

• Provides a way to choose between multiple options.
• Evaluates conditions from top to bottom, executing only the first true condition's block.
• Syntax:

  if(condition1) {
      // Executes if condition1 is true
  } else if(condition2) {
      // Executes if condition2 is true
  } else {
      // Executes if none above are true
  }
  

Jump Statements

• Control execution flow unconditionally.
• Types of jump statements in C include:
  • Break: Terminates loops or switch statements immediately.
  • Continue: Skips the current iteration and proceeds to the next iteration of the loop.
  • Goto: Jumps to a labeled statement in the code (less commonly used).
  • Return: Exits from a function and optionally returns a value.

Examples and Output

• If Statement Example:

  • Input: int i = 10; with if (i > 15).
  • Output: "I am Not in if" since the condition is false.

• If-Else Example:

  • Input: int i = 20; evaluates if i < 15.
  • Output: "i is greater than 15", as the condition fails.

• Nested If Example:

  • Input: int i = 10; with nested conditions.
  • Output: "i is smaller than 15" and "i is smaller than 12 too" confirmed by true evaluations.

• If-Else-If Ladder Example:

  • Input: int i = 20;.
  • Output: "i is 20", as it matches the specified condition.

• Break Statement Example:

  • Used within a loop for boolean checks to exit early when a condition is met.

• Continue Statement Example:

  • Forces the loop to skip any remaining code following it in the current iteration.