Calculating GCD of two numbers using Java

class GCD{
        public static void main(String args[])
        {
                int gcd=1;
                int n1=Integer.parseInt(args[0]);
                int n2=Integer.parseInt(args[1]);
                int num=n1<n2?n1:n2;
                if(num==1)
                        System.out.println("GCD of "+n1+" and "+n2+"="+gcd);
                else       
                {
                        for(int i=2;i<=num/2;i++)
                                if(n1%i==0&&n2%i==0)
                                        gcd=i;
                        System.out.println("GCD of "+n1+" and "+n2+"="+gcd);
                }
        }
}

Calculating roots of quadratic equation using Java

class Quad{
        public static void main(String args[])
        {
                int a,b,c;
                double d,r1,r2;
                a=Integer.parseInt(args[0]);
                b=Integer.parseInt(args[1]);
                c=Integer.parseInt(args[2]);
                d=b*b-4*a*c;
                if(d==0)
                {
                        r1=-b+Math.sqrt(d)/(2*a);
                        System.out.println("Roots are real and equal:\nRoot="+r1);
                }
                else if(d>0)
                {
                        r1=-b+Math.sqrt(d)/(2*a);
                        r2=-b-Math.sqrt(d)/(2*a);
                        System.out.println("Roots are real and unequal:\nRoot 1="+r1+"\nRoot 2="+r2);
                }
                else
                        System.out.println("Roots are imaginary.");
        }
}

Prime Numbers between 1 to 100 using Java

class Prime2{
        public static void main(String args[])
        {
                System.out.println("Prime numbers between 1 to 100 are:");
                int i=1,c=0,j;
                for(;i<=100;i++)
                {
                        for(j=2;j<=i/2;j++)
                                if(i%j==0)
                                        c++;
                        if(c==0)
                                System.out.print(i+" ");
                        c=0;
                }
        }
}

Checking Prime Number using Java

class Prime{
        public static void main(String args[])
        {
                int num=Integer.parseInt(args[0]),c=0;
                for(int i=2;i<=num/2;i++)
                        if(num%i==0)
                                c++;
                if(c==0)
                        System.out.println(num+" is a prime number.");
                else
                        System.out.println(num+" is not a prime number.");
        }
}
       

Armstrong Number

//Using Java
class Arm{
        public static void main(String args[])
        {
                int num=Integer.parseInt(args[0]);
                int temp=num,rem;
                double sum=0;
                while(temp!=0)
                {
                        rem=temp%10;
                        sum=sum+Math.pow(rem,3);
                        temp/=10;
                }
                if(sum==num)
                        System.out.println(num+" is an armstrong number.");
                else
                        System.out.println(num+" is not an armstrong number.");
        }
}

Lucas Series in Java

class Lucas{
public static void main(String args[])
{
   int n=Integer.parseInt(args[0]),num=1,i;//Input from command line
   for(i=0;i<n;i++)
   {
         num+=i;
         System.out.print(num+" ");
   }
}
}

Lucas Series

//Using C++
#include<iostream.h>
#include<conio.h>
#include<iomanip.h>
void main()
{
    int num=1,i,n;
    cout<<"Enter number of terms:";
    cin>>n;
    for(i=0;i<n;i++)
    {
        num=num+i;
        cout<<setw(2)<<num<<' ';
    }
    getch();
    clrscr();
}

Palindrome String WITHOUT using String Functions

//Using C++
#include<iostream.h>
#include<conio.h>
#include<stdlib.h>
void main()
{
    clrscr();
    char *wrd;
    int n=0;
    cout<<"Enter a string:";
    cin>>wrd;
    while(wrd[n]!='\0')
        n++;              //Counting length of the string
    n--;
    for(int i=0;i<n/2;i++,n--)
    {
        if(wrd[i]!=wrd[n])
        {
            cout<<"\nNot Palindrome!";
            getch();
            exit(0);
        }
    }
    cout<<"\nPalindrome.";
    getch();
}

Palindrome String using String Functions

//Using C++
#include<iostream.h>
#include<conio.h>
#include<string.h>
void main()
{
    char word[10],word2[10];
    int n;
    cout<<"Enter string:";
    cin>>word;
    strcpy(word2,word);
    strrev(word);
    if(stricmp(word,word2)==0)
        cout<<"\nPalindrome.";
    else
        cout<<"\nNot Palindrome!";
    getch();
    clrscr();
}

Deleting Duplicate Elements from an Array

/*Using C*/
#define size    10
#include<stdio.h>
#include<conio.h>
void main()
{
    int i,num[size],j;
    clrscr();
    printf("Enter %d numbers:",size);
    for(i=0;i<size;i++)
        scanf("%d",&num[i]);
    puts("The array is:");
    for(i=0;i<size;i++)
        printf("%d ",num[i]);
    for(i=0;i<size;i++)
        for(j=i+1;j<size;j++)
            if(num[i]==num[j])
                num[j]='\0';
    puts("\nUpdated array:");
    for(i=0;i<size;i++)
        printf("%d ",num[i]);
    getch();
}