3.1 Iteration minilab

Explain if, if-else, and if-elseif-else.

• if: runs code if a condition is true

boolean condition = true;
if (condition) {
    System.out.println("Condition is true");
}

Condition is true

• if-else: runs code if a condition is true, but if not, it will run different code

boolean condition = false;
if (condition) {
    System.out.println("Condition is true");
} else {
    System.out.println("Condition is not true");
}

• if-elseif-else: runs code if a condition is true, if not it does something else. Checks another condition if it were true, and again does something different if it is not.

boolean conditionA = true;
boolean conditionB = false;

if (conditionA) {
    System.out.println("Condition A is true");
} else {
    System.out.println("Condition A is not true");
} if (conditionB) {
    System.out.println("Condition B is true");
} else {
    System.out.println("Condition B is not true");
}

Condition A is true
Condition B is not true

Create and if-elseif-elseif-elsif-else statement, 5 or more conditions.

int val = 3;    // declares the value

if (val == 0) { // checks if value is 0
    System.out.println("Val: 0");  // prints value is 0 if it is true
} else if (val == 1) {  // if not check if value is 1
    System.out.println("Val: 1"); // prints value is 1 if it is true
} else if (val == 2) {  // if not check if value is 2
    System.out.println("Val: 2"); // etc
} else if (val == 3) { // etc
    System.out.println("Val: 3");
} else if (val == 4) {
    System.out.println("Val: 4");
}

Val: 3

Covert the 5 or more decisions to a switch-case-case-case-case-otherwise.

int val = 3;    // declares the value

switch (val) {  // declares the switch-case and the variable being tested is 'val'
    case 0: // if val is 0...
        System.out.println("Val: 0");   // print "Val: 0"
        break;  // leaves the code block (same thing a closing curly bracket does)
    case 1: // if val is 1...
        System.out.println("Val: 1");   // print "Val: 1"
        break;  // leaves the code block
    case 2:
        System.out.println("Val: 2");
        break;
    case 3:
        System.out.println("Val: 3");
        break;
    case 4:
        System.out.println("Val: 4");
        break;
}

Val: 3

Describe De Morgan's law

• not(A and B) = not A or not B
• not(A or B) = not A and not B
• the inverse of a function is equivalent to the same function with all variables being negative, and all ands/ors being switched

Illustrate De Morgan's law

boolean a = true;
boolean b = false;

if (a || b) {   // function 1
    System.out.println("function 1 passed");
} if (!(!a && !b)) {   // De Morgan function 1
    System.out.println("De Morgan function 1 passed");
}

function 1 passed
De Morgan function 1 passed
function 2 passed
De Morgan function 2 passed
function 3 passed
De Morgan function 3 passed

Show some code running that shows understanding

boolean a = true;
boolean b = false;

if (!(a && b) || (b || b)) {   // function 2
    System.out.println("function 2 passed");
} if (!(!(!a || !b) && (!b && !b))) {   // De Morgan function 2
    System.out.println("De Morgan function 2 passed");
}

function 2 passed
De Morgan function 2 passed