Ch 6Flow of Control — Class 11 Computer Science, concept-first.

Every program has an order in which its statements run, and controlling that order is what this chapter is about.

Real life is full of decisions. Standing in a stationery shop with 10 rupees, you find several different pens all priced at 10 rupees each — you must choose one.

How does Python know which statements belong to the if block and which come after it? Most programming languages answer this by wrapping the statements of a block inside curly brackets.

Many tasks in daily life repeat: the electricity bill is paid every month, seasons return every year. Nature repeats too — Figure 6.3 shows the life cycle of a butterfly, which passes through four sta…

The for statement is used to iterate over a range of values or a sequence. The loop body executes once for each item in that range.

The while statement executes a block of code repeatedly as long as the control condition of the loop is true.

Looping constructs let a programmer repeat tasks efficiently — but sometimes the normal round-and-round flow of a loop needs to be interrupted.

The break statement alters the normal flow of execution: it terminates the current loop immediately and resumes execution at the statement following that loop.

Where break abandons a loop entirely, the continue statement abandons only the current iteration. When continue is encountered, control skips the remaining statements in the body of the loop for that…

A loop may contain another loop inside its body. A loop placed inside another loop is called a nested loop.

- The order in which the statements of a program are executed is called the flow of control; it is shaped using control structures, of which Python supports two types — selection and repetition.