Program 1
//Write a program in JAVA to 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
//Write a program in JAVA to 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("The minimum number is "+result);
}
}
Program 3
/*
Write a program in JAVA 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 4
/*
Write a program to calculate 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 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 in JAVA 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 in JAVA 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 8
/*
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 9
/*
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 10
/*
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 11
/* 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 12
/* Write a program to Swap the values without using third variable */
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 13
/*
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 14
/*
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 15
/*
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 16
/*
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 17
/* 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(i%num==0)
if(i==num)
flag=1
if(flag==1)
System.out.println("The given number "+num+" is a prime number.");
else
System.out.println("The given number "+num+" isn't a prime number.");
}
}
Program 18
/*
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");
}
}
Some Java programs which help lot of java beginners to understand the basic fundamentals in Java programming. Most of these programs take input from the command line. Ex - int num = Integer.parseInt(args[0]);
Program 19
/*
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 20
/*
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 21
/*
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 22
/*
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 23
/*
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 24
/*
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");
}
}
}