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4. Loops

Introduction to loops

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while and for

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A loop repeats a block.

while (condition) { ... } checks the condition, runs the body, and checks again.

for (init; condition; step) { ... } is convenient when you count. A common pattern is for (int i = 1; i <= n; i++).

i++ means add one to i.

int i = 1;
while (i <= 3) {
    cout << i << endl;
    i++;
}

for (int j = 1; j <= 3; j++) {
    cout << j << endl;
}

Check 2

for-loop pieces

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In for (int i = 0; i < 5; i++), how many times does the body run?

Fill in 3

Loop keyword

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The loop that checks a condition before each pass and has no built-in counter is named

Try it 4

Print 1 through 5

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Run this for loop. Try changing 5 to 8.

main.cpp
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Output will appear here.

Assignment 5

Count to n

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Read an integer n. Print the numbers 1 through n, each on its own line. You may assume n is at least 1.

main.cpp
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switch statementswhile loops