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| 1 | +# 2 - Intro and Control flow |
| 2 | + |
| 3 | +[Slideshow](https://docs.google.com/presentation/d/1guorgyU68cKTfepvvsMLYtrrQHuN8Rys6UL-r0_Ztsk/edit) |
| 4 | + |
| 5 | +The recording will be published as soon as possible. |
| 6 | + |
| 7 | +The class went over: |
| 8 | +* Java basics (recap of [lesson 1](1-java-basics.md)) |
| 9 | +* Conditionals |
| 10 | +* For and while loops |
| 11 | + |
| 12 | +## Guide |
| 13 | + |
| 14 | +%% TODO |
| 15 | + |
| 16 | +## Demonstrated code |
| 17 | +```{code-block} java |
| 18 | +:caption: App.java |
| 19 | +:lineno-start: 1 |
| 20 | +
|
| 21 | +public class App { |
| 22 | + public static void main(String[] args) throws Exception { |
| 23 | + System.out.println("Hello, World!"); |
| 24 | + String str1 = "first string"; |
| 25 | + str1 = "second string"; |
| 26 | + System.out.println(str1); |
| 27 | +
|
| 28 | + int numOne = 4; |
| 29 | + int numTwo = 9; |
| 30 | + int numSum = numOne + numTwo; |
| 31 | + int numDiff = numOne - numTwo; |
| 32 | + int numProd = numOne * numTwo; |
| 33 | + int numQuot = numOne / numTwo; |
| 34 | + System.out.println(numSum); |
| 35 | + System.out.println(numDiff); |
| 36 | + System.out.println(numProd); |
| 37 | + System.out.println(numQuot); |
| 38 | +
|
| 39 | + int a = 5; |
| 40 | + int b = 10; |
| 41 | +
|
| 42 | + if (a==b){ |
| 43 | + System.out.println("a = b"); |
| 44 | + } |
| 45 | + else if (a<b){ |
| 46 | + System.out.println("a < b"); |
| 47 | + } |
| 48 | + else{ |
| 49 | + System.out.println("a > b"); |
| 50 | + } |
| 51 | +
|
| 52 | + if (a < 10 && b > 5){ |
| 53 | + System.out.println("a is less than 10 AND b is greater than 5"); |
| 54 | + } |
| 55 | + else if (a < 10 || b < 5 || !(a==b)) { |
| 56 | + System.out.println("a is less than 10 OR b is less than 5"); |
| 57 | + } |
| 58 | + else if (a!=b) { |
| 59 | + System.out.println("a is NOT equal to b"); |
| 60 | + } |
| 61 | + else { |
| 62 | + System.out.println("neither of the conditions were true"); |
| 63 | + } |
| 64 | + int j = 0; |
| 65 | + while (j<5){ |
| 66 | + System.out.println("j is currently: " + j); |
| 67 | + j++; |
| 68 | + } |
| 69 | +
|
| 70 | + for (int y = 0; y<=3; y++){ |
| 71 | + System.out.println("Outer loop y = " + y); |
| 72 | + for (int z = 1; z <=2; z++){ |
| 73 | + System.out.println(" Inner loop z = " + z); |
| 74 | + } |
| 75 | + } |
| 76 | + } |
| 77 | +} |
| 78 | +``` |
| 79 | + |
| 80 | +## Exercise |
| 81 | + |
| 82 | +* Write a program to check if the grade percentage in a variable is an A, B, C, or D. |
| 83 | + * A = 90+, B = 80+, C = 70+, D = 0-69.9 |
| 84 | + * Use a loop to go through numbers from 50 to 94, inclusive |
| 85 | + * In increments of 4 |
| 86 | + |
| 87 | +* Hint: |
| 88 | + * Think about what type of loop would be better |
| 89 | + * How you would increase something by 4 and use it? |
| 90 | + |
| 91 | +### Solution |
| 92 | + |
| 93 | +:::{dropdown} Solution |
| 94 | +```{code-block} java |
| 95 | +:caption: GradeChecker.java |
| 96 | +:lineno-start: 1 |
| 97 | +
|
| 98 | +public class GradeChecker { |
| 99 | + public static void main(String[] args) { |
| 100 | + // Loop from 50 to 94 in increments of 4 |
| 101 | + for (int grade = 50; grade <= 94; grade += 4) { |
| 102 | + // Check grade category |
| 103 | + if (grade >= 90) { |
| 104 | + System.out.println("Grade " + grade + " = A"); |
| 105 | + } else if (grade >= 80) { |
| 106 | + System.out.println("Grade " + grade + " = B"); |
| 107 | + } else if (grade >= 70) { |
| 108 | + System.out.println("Grade " + grade + " = C"); |
| 109 | + } else { |
| 110 | + System.out.println("Grade " + grade + " = D"); |
| 111 | + } |
| 112 | + } |
| 113 | + } |
| 114 | +} |
| 115 | +``` |
| 116 | +::: |
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