What this chapter is about
So far, we've written programs that execute statements sequentially—one after another from beginning to end. Yet most real programs need more sophisticated behavior. A program must make decisions: "If user is an adult, allow access; otherwise, deny." It must repeat operations: "Process each student's grades and calculate averages." It must handle multiple scenarios: "If password is correct, log in; if incorrect three times, lock account." This conditional and repetitive behavior is fundamental to programming. Flow of control refers to the order in which statements execute. Without control structures, all programs would execute identically every time—clearly inadequate. Python provides two main types of control structures: selection (making decisions with if-elif-else) and repetition (looping with for and while). Understanding these structures is essential for writing practical programs that respond to varying inputs and conditions. This chapter explores conditional statements, loop structures, and how to combine them for complex program behavior.
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Learning objectives
- 1Explain conditional Statements, Loops, and Program Logic
- 2Explain sequential Flow
- 3Explain selection (Conditional Flow)
- 4Explain repetition (Loop Flow)
- 5Explain sELECTION/CONDITIONAL STATEMENTS
- 6Explain if Statement