Java Exercises for you

JAVA Exercises for you

1 1. What would be output of the following code segment written in java.

public static void main(String [] args)

{ int a=10, b= 9;

boolean x;

x = a++ == ++b;

System.out.print("x = "+x); }

2 2. Find the output of the following code snippet written in java

public static void main(String []args)

{

int x=10, y=5;

System.out.println(x++);

System.out.println(++y);

System.out.println((x++ + ++y));

System.out.println((++x - y++));

System.out.println((x++) + (++y));

System.out.println((++x)-(y++));

System.out.println((x++) + (++x));

System.out.println("x = "+ X +" y="+ y);

}

3 3. Find the output of the following code snippet written in java

public static void main(String []args)

{

long a=78345,s1=0,s2=0,r;

while(a>0)

{

r=a%10;

if (r%4==0)

s1+= r;

else

s2+=r;

a/=10;

}

System.out.println("S1 ="+ s1);

System.out.println("S2 ="+ s2);

}

4 4. Find the output of the following code snippet written in java

public static void main(String args[])

{

int no1=2,no2=1,i;

while(no2<=3)

{

i=no1;

while(i<=no2)

{

no1=no1*i;

i++;

}

System.out.println("No1 "+ no1);

System.out.println("No2 "+ no2);

no2++;

}

5 5. the output of the following code snippet written in java

public static void main(String args[])

{

int x=1,y=1,z=1,i=1;

while(y<=3)

{

z=1;

while(z<=y)

{ x=x*i;

i++; z++;

}

System.out.println("x= "+x);

y++; } }

6 6. Find the output of the following code segment written in JAVA. Assume all necessary header files have been included and ignore any syntax error if any.

public static void main(String [] args)

{

int i = 3, a=0, b=1, n=5, c;

System.out.print(a+ “ “+b+” “);

while ( i < n)

{ c= a + b;

System.out.print(c+” “);

a = c - a;

b = c;

i++; } }

7 7. How many times will the following loop get executed and what will be the final value of the variable I after execution the loop is over.

int I = 5;

{ I += 3;

System.out.println("I = "+I);

I = I + 1; }

while (I >= 9);

8 8. Correct the errors in the following program segment written in JAVA. You are just required to write the corrected code, underlying the corrections made.

Public Static Void Main (String [] args)

{

Integer Nos = 100;

while (Nos => 45)

{

If (Nos % 5 = 0);

Nos+=10;

otherwise

Nos + = 20; } }

9 9. Convert the following ‘while loop’ into its equivalent ‘for loop without altering the output of the program.

int x = 100, a = 30;

while ( x>= 10)

{

System.out.println(”New Amount =”+(x + a));

a++;

x - = a;

}

10. Predict the output:

a) String name=”TATA”;

int i=0;

While(i<name.length())

{

System.out.println(name.substring(I,i+1));

i++;

}

b) int a=1;

int count=20;

{

a=a*count;

count=count-2;

} while(count<10);

system.out.print(a);

c) Given a string object names salary having value as ‘55000” stored in it ., Obtain the output of the following:

JoptionPane.showMessageDialog(null,+salary.length()+Integer.parseInt(salary));

d) String a=”abc”;

System.out.println(a+”abc”+”12”);

e) Int a =5,b=10;

If(a>5)

If(b>5)

System.out.print(b);

Else

System.out.print(a);

System.out.print(“notvalid”);

f) for(int a= 40;a>10;a--)

Int f=f*a;

System.out.print(f);

g) jTextArea1.setText(“India\nIncredible\n\tIndia”);

h) int x=20;

int y=10;

int z=0;

if((++y<x--)||(y!=5))

{

System.out.println(x++);

System.out.println(y);

Z=++y+ ++x;

System.out.println(z)

System.out.println(x);}

1 11. Predict the output:

For(int i=1;i<4;i++)

{

For(int j=1;j<I;j++)

System.out.print(i+” “);

System.out.println();}

Predict the output:

a)Int val1-5,val2=10;

For(int i=1;i<=3;i++)

{

System.out.println(val1++ + “,”+ --val2);

System.out.println(val2--+ “,” + ++val1);

}

b)Int i=10,j=3;

Switch(i/%j)

{

Case 0: System.out.print(“hello”);

Break;

Case 1: system.out.print(“welcome”);

Break;

Case2: system.out.print(“not welcome”);

Break;

}

1 12. Convert the following switch into if else

Int j;

J=integer.parseInt(jTextField1.getText());

Switch(j)

{

Case 100: j=j*j;

Case 200: j=j+j;

Break;

Case 300: j=j-j;

Case 400:j=j+2;

Break;

Default:j=j+8;

}

1 13. Predict output:

Public static void main(string[] args)

{

String fullname=”bill gates”;

String firstname =””;

Firstname=fullname.substring(0,2);

System.out.print(firstname);

Firstname= FullName.substring(5, 2);

System.out.print(firstname);

Firstname= FullName.substring( 5, FullName.length( ) - 3 );

System.out.print(firstname);

}

1 14. Predict output:

String s1 = "Amit";

String s2 = "Amit";

String s3 = abcd";

String s4 = abcd";

System.out.println(s1.equals(s2));

System.out.println((s1==s2));

System.out.println(s3.equals(s4));

System.out.println((s3==s4));

1 15. What will be the values of x and y after execution of the following code:

int x,y=0;

for(x=1;x<=5;++x)

y=x++ + ++x;

--y;

16. Find the output of the following statements.

jTextField1.setText(Integer.parseInt(“21”+100)+100);

jTextField1.setText(“CBSE\nFinal\tExam”);

1 16. What values will be assigned to the variable ua , ub, uc and fail after execution of the following program segment:

int i=0,ua=0,ub=0,uc=0,fail=0;

while(i<=5) {

Switch ( i++ ) {

case 1 :++ua;

case 2 : ++ub; uc++;break;

case 3 :

case 4 : ++uc; ua++;ub++;break;

default : ++fail; } }

1 17. The following code has some error(s).Rewrite the correct code underlining all the corrections made:

int SUM=0,Step=5;

int I;

For(i=0;i=<5;++i)

{ Step+=5;

Sum+=Step;}

jTextField1.showText(Double.toString(SUM));

1 18. What will be the value of P and Q after execution of the following code?

int P,Q = 100

for (P=10; P<12; P++)

{

Q+ = P;

}

JOptionPane. showMessageDialog(this, “p + “+P+” Q;”+Q+” );

19. What will be the constants of jTextField1 and jTextField2 after executing the following code:

i) jTextField1.setText(Math.round(25.7)+ “ ”);

ii) jTextField2.setText(Math.pow(2,3)+ “ ”);

20. What will be the contents of F1 and F2 after the following code is executed?

String F1=”hello”, F2=”Friend”;

F1=F1.concat(F2);

21.Given the following code fragment :Write an alternative code using switch case.

If(a==0)

{

If(a==1)

System.out.println(“zero”);

System.out.println(“one”);

}

If(a==2)

System.out.println(“two”);

If(a==3)

System.out.println(“three”);

22.Predict an output of the following code fragments:

int i = 1, j = 0, n = 0;

while(i<4) {

for(j=1;j<= i ; j++)

{ n+= 1;

i = i+1;

}

System.out.println(n);

}

23. What will be an output of the following code:

int i,j,n;

n=0; i=1;

{ n++; i++;

System.out.println(n+” “+i);

}while(i<=5);

24.Predict the output of following code fragments:

(a) int i, j, n;

n=0; i=1;

n++; i++;

} while (i<=5);

i=i+1;

} System.out.print ln(n);

(b) int i1,j=0,n=0;

While(i<4)

{

for(j=1;j<=I;j++)

{

n+=1;

}

System.out.print ln(n);

while (i<4) {

n++; i--;

System.out.print ln(n);

(d) int j=1,s=0;

While(j<10)

{

System.out.print(j+ “+”);

s=s+j;

j=j+j%3;}

System.out.print ln(“=”+s);

25. Find out errors if any;

(a) m=1;

n=0; sum=sum + a;

System.out.print ln(“Hello \n”);

m=m+10;

(b) while(ctr !=10) ; {

ctr=1;

for(;m+n<19;++n)

ctr=ctr + 1;

}

26. Find errors in the following code :

Import java.sql* ;

:connection conn =

DriveManager.getconnention(“jdbc:mysql://localhost/test”,”root”,”wxyz);

Statement stmt = con.createstatement();

Sql= “SELECT empno,emame,job,sal From EMPL; “ ;

Resultset rs = stmt.executeQuery(sql); }

Catch(Exception e) { }

27.What will be the output after executing the following code?

int fun(int n)

{ int r=(n%2==0)?1:0;

return r; }

int t=5,p;

{ p=fun(t);

if(p==1)

System.out.println(t+p);

else

System.out.print(t+p);

}while(++t<10);

28. The following code has error(s). Rewrite the correct code underlining all the corrections made

int Sum = 1 , Step = 5 ;

int i ;

for ( i = 0 ; i < = 5 , i ++) ;

{

Step += 5 ,

Sum += Step ;

}

jTextArea1 . showText ( " " + Sum )

29. Find out errors if any:

int i; sum= 0;

i=1 ;

while (i<=5)

{

sum =sum +i

i+=3

} System.out.println(sum) ;

30.Predict the output:

a. Predict the output of the following code fragments:

int val1 =5; val2=10;

for(int i=1;i<=3;i++)

system.out.println(“ “ +val1++ + “,” + --val2);

system.out.println(“ “ +val2-- + “,” +++va12);

b. How many times the loop gets executed and write the output.

int x=0;

do{

System.out.print(“Welcome to MYSQL”);

}while(x!=0);

31. Rewrite the following code using while loop :

a. int i,j;

for(i=1,j=2;i<=6;i++,j+=2)

System.out.println(i++);

System.out.println(“Finished!!!”);

b. Rewrite the following code using do.. while loop

int sum=0, i=1;

while(i<=5)

{

sum=sum+i;

}