CS1325_Chap4_Slides_PPT - Tagged

Chapter 4: C Program Control

Objectives

  • Learn about counter-controlled iteration.

  • Use for and do while iteration statements.

  • Understand multiple selection using the switch statement.

  • Use break and continue statements to alter control flow.

  • Form complex conditional expressions using logical operators.

  • Avoid confusion between equality and assignment operators.

Section 4.2: Iteration Essentials

  • Definition of a Loop: A group of instructions executed repeatedly while a condition remains true.

  • Types of Iteration:

    • Count-controlled iteration: Uses a control variable to count iterations.

    • Sentinel-controlled iteration: Uses a sentinel value to control iteration when the number of iterations is unknown.

Section 4.3: Counter-Controlled Iteration

  • Requirements:

    • Loop control variable (counter).

    • Initial value of the control variable.

    • Update mechanism for the control variable.

    • Condition to test for the final value of the control variable.

  • Common Error: Avoid using floating-point values for counting loops due to imprecision.

Section 4.4: The for Iteration Statement

  • Purpose: Specifically designed for count-controlled loops.

  • Format:

    for (initialization; condition; update) {
    statement;
}

  • Example: Displaying values from 1 to 10 using a for loop.

Section 4.6: Example - Compound-Interest Calculation

  • Problem Statement: Calculate and print the amount in a savings account over 10 years with a 5% interest rate.

  • Formula: ( a = p(1 + r)^n )

  • Implementation: Use a loop to perform calculations for each year.

Section 4.7: switch Multiple-Selection Statement

  • Purpose: Handle multiple decisions based on a variable's value.

  • Structure:

    switch (expression) {
    case value1:
        // action
        break;
    default:
        // default action
}

  • Execution: Compares the switch expression with case labels and executes the corresponding action.

Section 4.8: do while Iteration Statement

  • Definition: Tests the loop condition after executing the loop body, ensuring at least one execution.

  • Format:

    do {
    statement;
} while (condition);

Section 4.9: break and continue Statements

  • break Statement: Exits the loop immediately.

  • continue Statement: Skips the remaining statements in the loop body and begins the next iteration.

  • Usage Note: Avoid using break to exit loops in structured programming.

Section 4.10: Logical Operators

  • Operators:

    • && (logical AND)

    • || (logical OR)

    • ! (logical NOT)

  • Short-Circuit Evaluation: Evaluation stops as soon as the result is known.

Section 4.12: Structured Programming Summary

  • Principles:

    • Single entry and exit points in control statements.

    • Control statements connected in simple ways.

Section 4.13: Secure C Programming

  • Checking Return Values: Always check the return value of functions like scanf to ensure successful input.

  • Range Checking: Validate input values to ensure they fall within expected ranges (e.g., grades between 0 and 100).