### Core java programs

by : -  Hardik  H. Kothadia        C.E.        R.K.  UNIVERSITY
CONT......         8 00 00 4 99 53

Program 1
//Find Maximum of 2 nos.
class Maxof2{
public static void main(String args[]){
//taking value as command line argument.
//Converting String format to Integer value
int i = Integer.parseInt(args[0]);
int j = Integer.parseInt(args[1]);
if(i > j)
System.out.println(i+" is greater than "+j);
else
System.out.println(j+" is greater than "+i);
}
}

Program 2

//Find Minimum of 2 nos. using conditional operator
class Minof2{
public static void main(String args[]){
//taking value as command line argument.
//Converting String format to Integer value
int i = Integer.parseInt(args[0]);
int j = Integer.parseInt(args[1]);
int result = (i<j)?i:j;
System.out.println(result+" is a minimum value");
}
}

Program 3

/* Write a program that will read a float type value from the   keyboard and print the following output.

->Small Integer not less than the number.

->Given Number.

->Largest Integer not greater than the number.

*/
class ValueFormat{
public static void main(String args[]){
double i = 34.32; //given number
System.out.println("Small Integer not greater than the number : "+Math.ceil(i));
System.out.println("Given Number : "+i);
System.out.println("Largest Integer not greater than the number : "+Math.floor(i));
}

Program 4

/*Write a program to generate 5 Random nos. between 1 to 100, and it

should not follow with decimal point.

*/
class RandomDemo{
public static void main(String args[]){
for(int i=1;i<=5;i++){
System.out.println((int)(Math.random()*100));
}
}
}

Program 5

/* Write a program to display a greet message according to

Marks obtained by student.

*/
class SwitchDemo{
public static void main(String args[]){
int marks = Integer.parseInt(args[0]);                //take marks as command line argument.
switch(marks/10){
case 10:
case 9:
case 8:
System.out.println("Excellent");
break;
case 7:
System.out.println("Very Good");
break;
case 6:
System.out.println("Good");
break;
case 5:
System.out.println("Work Hard");
break;
case 4:
System.out.println("Poor");
break;
case 3:
case 2:
case 1:
case 0:
System.out.println("Very Poor");
break;
default:
System.out.println("Invalid value Entered");
}
}
}

Program 6

/*Write a program to find SUM AND PRODUCT of a given Digit. */
class Sum_Product_ofDigit{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);         //taking value as command line argument.
int temp = num,result=0;
//Logic for sum of digit
while(temp>0){
result = result + temp;
temp--;
}
System.out.println("Sum of Digit for "+num+" is : "+result);
//Logic for product of digit
temp = num;
result = 1;
while(temp > 0){
result = result * temp;
temp--;
}
System.out.println("Product of Digit for "+num+" is : "+result);
}
}

Program 7

/*Write a program to Find Factorial of Given no. */
class Factorial{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);                 //take argument as command line
int result = 1;
while(num>0){
result = result * num;
num--;
}
System.out.println("Factorial of Given no. is : "+result);
}
}

Program 8

/*Write a program to Reverse a given no. */
class Reverse{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);               //take argument as command line
int remainder, result=0;
while(num>0){
remainder = num%10;
result = result * 10 + remainder;
num = num/10;
}
System.out.println("Reverse number is : "+result);
}
}

Program 9

/*Write a program to find Fibonacci series of a given no.

Example :

Input - 8

Output - 1 1 2 3 5 8 13 21

*/
class Fibonacci{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);                        //taking no. as command line argument.
System.out.println("*****Fibonacci Series*****");
int f1, f2=0, f3=1;
for(int i=1;i<=num;i++){
System.out.print(" "+f3+" ");
f1 = f2;
f2 = f3;
f3 = f1 + f2;
}
}
}

Program 10
/* Write a program to find sum of all integers greater than 100 and
less than 200 that are divisible by 7 */
class SumOfDigit{
public static void main(String args[]){
int result=0;
for(int i=100;i<=200;i++){
if(i%7==0)
result+=i;
}
System.out.println("Output of Program is : "+result);
}
}

Program 11

/* Write a program to Concatenate  string using for Loop

Example:
Input - 5
Output - 1 2 3 4 5 */
class Join{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
String result = " ";
for(int i=1;i<=num;i++){
result = result + i + " ";
}
System.out.println(result);
}
}

Program 12
/* Program to Display Multiplication Table */
class MultiplicationTable{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
System.out.println("*****MULTIPLICATION TABLE*****");
for(int i=1;i<=num;i++){
for(int j=1;j<=num;j++){
System.out.print(" "+i*j+" ");
}
System.out.print("\n");
}
}
}

Program 13
/* Write a program to Swap the values */
class Swap{
public static void main(String args[]){
int num1 = Integer.parseInt(args[0]);
int num2 = Integer.parseInt(args[1]);
System.out.println("\n***Before Swapping***");
System.out.println("Number 1 : "+num1);
System.out.println("Number 2 : "+num2);
//Swap logic
num1 = num1 + num2;
num2 = num1 - num2;
num1 = num1 - num2;
System.out.println("\n***After Swapping***");
System.out.println("Number 1 : "+num1);
System.out.println("Number 2 : "+num2);
}
}

Program 14
/* Write a program to convert given no. of days into months and days.
(Assume that each month is of 30 days)
Example :
Input - 69
Output - 69 days = 2 Month and 9 days */
class DayMonthDemo{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
int days = num%30;
int month = num/30;
System.out.println(num+" days = "+month+" Month and "+days+" days");
}
}

Program 15
/*Write a program to generate a Triangle.
eg:
1
2 2
3 3 3
4 4 4 4 and so on as per user given number */
class Triangle{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
for(int i=1;i<=num;i++){
for(int j=1;j<=i;j++){
System.out.print(" "+i+" ");
}
System.out.print("\n");
}
}
}

Program 16
/* Write a program to Display Invert Triangle.
Example:
Input - 5
Output :
5 5 5 5 5
4 4 4 4
3 3 3
2 2
1
*/
class InvertTriangle{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
while(num > 0){
for(int j=1;j<=num;j++){
System.out.print(" "+num+" ");
}
System.out.print("\n");
num--;
}
}
}

Program 17
/*Write a program to find whether given no. is Armstrong or not.
Example :
Input - 153
Output - 1^3 + 5^3 + 3^3 = 153, so it is Armstrong no. */
class Armstrong{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
int n = num; //use to check at last time
int check=0,remainder;
while(num > 0){
remainder = num % 10;
check = check + (int)Math.pow(remainder,3);
num = num / 10;
}
if(check == n)
System.out.println(n+" is an Armstrong Number");
else
System.out.println(n+" is not a Armstrong Number");
}
}

Program 18
/* Write a program to Find whether number is Prime or Not. */
class PrimeNo{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
int flag=0;
for(int i=2;i<num;i++){
if(num%i==0)
{
System.out.println(num+" is not a Prime Number");
flag = 1;
break;
}
}
if(flag==0)
System.out.println(num+" is a Prime Number");
}
}

Program 19
/* Write a program to find whether no. is palindrome or not.
Example :
Input - 12521 is a palindrome no.
Input - 12345 is not a palindrome no. */
class Palindrome{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
int n = num; //used at last time check
int reverse=0,remainder;
while(num > 0){
remainder = num % 10;
reverse = reverse * 10 + remainder;
num = num / 10;
}
if(reverse == n)
System.out.println(n+" is a Palindrome Number");
else
System.out.println(n+" is not a Palindrome Number");
}
}

Program 20
/* switch case demo
Example :
Input - 124
Output - One Two Four */

class SwitchCaseDemo{
public static void main(String args[]){
try{
int num = Integer.parseInt(args[0]);
int n = num; //used at last time check
int reverse=0,remainder;
while(num > 0){
remainder = num % 10;
reverse = reverse * 10 + remainder;
num = num / 10;
}
String result=""; //contains the actual output
while(reverse > 0){
remainder = reverse % 10;
reverse = reverse / 10;
switch(remainder){
case 0 :
result = result + "Zero ";
break;
case 1 :
result = result + "One ";
break;
case 2 :
result = result + "Two ";
break;
case 3 :
result = result + "Three ";
break;
case 4 :
result = result + "Four ";
break;
case 5 :
result = result + "Five ";
break;
case 6 :
result = result + "Six ";
break;
case 7 :
result = result + "Seven ";
break;
case 8 :
result = result + "Eight ";
break;
case 9 :
result = result + "Nine ";
break;
default:
result="";
}
}
System.out.println(result);
}catch(Exception e){
System.out.println("Invalid Number Format");
}
}
}

Program 21
/* Write a program to generate Harmonic Series.
Example :
Input - 5
Output - 1 + 1/2 + 1/3 + 1/4 + 1/5 = 2.28 (Approximately) */
class HarmonicSeries{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
double result = 0.0;
while(num > 0){
result = result + (double) 1 / num;
num--;
}
System.out.println("Output of Harmonic Series is "+result);
}
}

Program 22
/*Write a program to find average of consecutive N Odd no. and Even no. */
class EvenOdd_Avg{
public static void main(String args[]){
int n = Integer.parseInt(args[0]);
int cntEven=0,cntOdd=0,sumEven=0,sumOdd=0;
while(n > 0){
if(n%2==0){
cntEven++;
sumEven = sumEven + n;
}
else{
cntOdd++;
sumOdd = sumOdd + n;
}
n--;
}
int evenAvg,oddAvg;
evenAvg = sumEven/cntEven;
oddAvg = sumOdd/cntOdd;
System.out.println("Average of first N Even no is "+evenAvg);
System.out.println("Average of first N Odd no is "+oddAvg);

}
}

Program 23
/* Display Triangle as follow : BREAK DEMO.
1
2 3
4 5 6
7 8 9 10 ... N */
class Output1{
public static void main(String args[]){
int c=0;
int n = Integer.parseInt(args[0]);
loop1: for(int i=1;i<=n;i++){
loop2: for(int j=1;j<=i;j++){
if(c!=n){
c++;
System.out.print(c+" ");
}
else
break loop1;
}
System.out.print("\n");
}
}
}

Program 24
/* Display Triangle as follow
0
1 0
1 0 1
0 1 0 1 */
class Output2{
public static void main(String args[]){
for(int i=1;i<=4;i++){
for(int j=1;j<=i;j++){
System.out.print(((i+j)%2)+" ");
}
System.out.print("\n");
}
}
}

Program 25
/* Display Triangle as follow
1
2 4
3 6 9
4 8 12 16 ... N (indicates no. of Rows) */
class Output3{
public static void main(String args[]){
int n = Integer.parseInt(args[0]);
for(int i=1;i<=n;i++){
for(int j=1;j<=i;j++){
System.out.print((i*j)+" ");
}
System.out.print("\n");
}
}

}