1. Conditionals and Loops
COMP 202 – Tutorial 3
Conditionals and Loops

2. If, Else if (x == z && z == (y – 16)) { int x = 7; v = 2*x + y;
int y = 23;
int z = y – 16;
int w, v;
if (x == y) {
w = 2*x; }
else
w = 2*y;
if (x == z && z == (y – 16)) {
v = 2*x + y;
w = v + 1; }
else {
w = 2*y + z;
v = w – 1;
System.out.println(w + “ “ + v);
// What comes out?

3. String name1 = “Neumann”;
if (name1.equals(name2))
System.out.println(name1);
else if (name2 == name3)
System.out.println(name3);
else
System.out.println(“No match”);

4. int x = scan.nextInt();
int y;
if (x >0) if (x > 0)
y = 1; y = 1;
if (x < 0) else if (x < 0)
y = -1; y = -1;
if (x == 0) else if (x == 0)
y = 0; y = 0;

5. A complicated example int x = 6; int y = 7; int z = 22; int w = 22;
int v = 0;
if (x == y || z == w)
if (y == w)
v = z + x;
else if (y == w) // else belongs to second if
v = z – x;
// an else corresponds to the last if before it.

6. A complicated example int x = 6; int y = 7; int z = 22; int w = 22;
int v = 0;
if (x == y || z == w) {
if (y == w)
v = z + x; }
else if (y == w) // NOW else belongs to first if
v = z – x;

7. The Conditional Statement
int x = scan.nextInt();
int y = scan.nextInt();
int z = (x <= y) ? x+2 : y+2;

8. for int i, j; for (i = 0; i < 27; i++) j = i^2; int j = 23;
for (int i = 0; i < j; i++)
System.out.println(i);

9. Nested for Loop int x,y; for (x = 0; x != 3; x++) {
for (y = 0; y != 3; y++)
System.out.println("Coordinate "+x+","+y); }

10. while int i,j; int j = 23; i = 0; int i = 0; while (i<27){
j = i^2;
i++; }
int j = 23;
int i = 0;
while (i < j) {
System.out.println(i);
i++; }

11. do while int i,j; int j = 23; i = 0; int i = 0; do do { {
// Will happen at least once
int j = 23;
int i = 0; do {
System.out.println(i);
i++
} while (i < j);

12. Torment
A user is required to pay $230 through a program. Use any loops/conditionals so that the user enters an amount. Then check if the amount is correct, and ask the user to modify it if not.

13. Answer – for Scanner scan = new Scanner(System.in);
final int AMOUNT = 230; // turned to constant
int payment = 0;
int modification = 0;
for (/*empty field*/ ; payment != AMOUNT ; payment+=modification) {
System.out.println("Payment given so far: " + payment);
System.out.println("Please enter your payment/deduction:");
if (payment < AMOUNT)
modification = scan.nextInt();
// If the user over-payed, the next modification will be a deduction.
else modification = - scan.nextInt(); }

14. Answer – do-while Scanner scan = new Scanner(System.in);
final int AMOUNT = 230; // turned to constant
int payment = 0;
int modification = 0; do {
System.out.println("Please enter your payment/deduction:");
if (payment < AMOUNT)
payment += scan.nextInt();
else payment -= scan.nextInt();
System.out.println("Payment given so far: " payment);
} while (payment != AMOUNT);