KembaraXtra-Computer Science- Program Flow

Program Flow: Controlling What Your Code Does

Core Idea: Program flow (or control flow) lets your program make decisions and repeat actions based on conditions.

1. If Statements: Doing Something Based on a Condition

Purpose: Executes a block of code only if a specified condition is true. Optionally includes else to execute a different block if the condition is false.

Basic Structure:

Python:

if condition:
    # Code to execute if condition is true
else:
    # Code to execute if condition is false

if (condition) {
    // Code to execute if condition is true
} else {
    // Code to execute if condition is false
}

Key Differences (Python vs. C):

Code Blocks:

Python: Uses indentation to define code blocks (lines with the same indentation level belong to the same block).
C: Uses curly braces {} to define code blocks. Braces can be omitted for single-line blocks.

elif (Python) / else if (C): Used to check multiple conditions in sequence. The elif/else if condition is only evaluated if the preceding if or elif/else if condition was false.

Python:

if condition1:
    # Code for condition1
elif condition2:
    # Code for condition2
else:
    # Code if neither condition1 nor condition2 is true

if (condition1) {
    // Code for condition1
} else if (condition2) {
    // Code for condition2
} else {
    // Code if neither condition1 nor condition2 is true
}

2. Looping: Repeating Actions

Purpose: Executes a block of code repeatedly.

Types:

while loop: Repeats as long as a condition is true.

Python:

while condition:
    # Code to repeat

while (condition) {
    // Code to repeat
}

Important: Make sure the condition eventually becomes false to avoid an infinite loop!

for loop: Iterates over a sequence of values (numbers, items in a list, etc.).

C Style (for with numeric range):

for (initialization; condition; increment/decrement) {
    // Code to execute in each iteration
}

initialization: Executed once at the beginning of the loop (e.g., int x = 1;).
condition: Checked before each iteration. The loop continues as long as the condition is true (e.g., x <= 10;).
increment/decrement: Executed after each iteration (e.g., x++;).

Python Style (for with collection):

for item in collection:
    # Code to execute for each item in the collection

collection: A list, tuple, string, or other iterable object.
item: A variable that takes on the value of each item in the collection during each loop iteration.

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