# Question from Dan Chisholm's mock exam

harsha puttaswamy

Greenhorn

Posts: 24

posted 11 years ago

class JMM106 {

public static void main(String args[]) {

int x = -5; int success = 0;

do {

switch(x) {

case 0: System.out.print("0"); x += 5; break;

case 1: System.out.print("1"); x += 3; break;

case 2: System.out.print("2"); x += 1; break;

case 3: System.out.print("3"); success++; break;

case 4: System.out.print("4"); x -= 1; break;

case 5: System.out.print("5"); x -= 4; break;

case 6: System.out.print("6"); x -= 5; break;

default: x += x < 0 ? 2 : -2;

}

} while ((x != 3) || (success < 2));

}}

Answer is :- 1433.

Can someone please explain to me what exactly happens in the default section ? For some reason I am thinking x should be set to 2 in the first step because x will be less than 10. But, it turns out that x evaluates to -3 in the first step.

Thank you,

Harsha.

public static void main(String args[]) {

int x = -5; int success = 0;

do {

switch(x) {

case 0: System.out.print("0"); x += 5; break;

case 1: System.out.print("1"); x += 3; break;

case 2: System.out.print("2"); x += 1; break;

case 3: System.out.print("3"); success++; break;

case 4: System.out.print("4"); x -= 1; break;

case 5: System.out.print("5"); x -= 4; break;

case 6: System.out.print("6"); x -= 5; break;

default: x += x < 0 ? 2 : -2;

}

} while ((x != 3) || (success < 2));

}}

Answer is :- 1433.

Can someone please explain to me what exactly happens in the default section ? For some reason I am thinking x should be set to 2 in the first step because x will be less than 10. But, it turns out that x evaluates to -3 in the first step.

Thank you,

Harsha.

sethu chiyan

Greenhorn

Posts: 10

posted 11 years ago

Hi Harsha,

// code here

default: x += x < 0 ? 2 : -2;// Evaluation explained below

In First time Loop

Current x value is -5 as v know

x+= (x<0) ? 2 : -2

x += (-5<0) ? 2: -2

x+=2;

so x = -3 in 1rst iteration

In second time Loop

Current x value is -3 as v know

x+= (x<0) ? 2 : -2

x += (-3<0) ? 2: -2

x+=2;

so x = -1 in 2nd iteration

In Third time Loop

Current x value is -1 as v know

x+= (x<0) ? 2 : -2

x += (-1<0) ? 2: -2

x+=2;

so x = 1 in 2nd iteration

Then as v know it goes like this

System.out.print("1");

System.out.print("4");

System.out.print("3");

System.out.print("3");

So the O/P is 1433.

Hope this will help u.

Pl do contact me if u r still in trouble,

with regards,

Chiyan.

// code here

default: x += x < 0 ? 2 : -2;// Evaluation explained below

In First time Loop

Current x value is -5 as v know

x+= (x<0) ? 2 : -2

x += (-5<0) ? 2: -2

x+=2;

so x = -3 in 1rst iteration

In second time Loop

Current x value is -3 as v know

x+= (x<0) ? 2 : -2

x += (-3<0) ? 2: -2

x+=2;

so x = -1 in 2nd iteration

In Third time Loop

Current x value is -1 as v know

x+= (x<0) ? 2 : -2

x += (-1<0) ? 2: -2

x+=2;

so x = 1 in 2nd iteration

Then as v know it goes like this

System.out.print("1");

System.out.print("4");

System.out.print("3");

System.out.print("3");

So the O/P is 1433.

Hope this will help u.

Pl do contact me if u r still in trouble,

with regards,

Chiyan.