Write a java program to swap two numbers

public class SwapNumbers {

    public static void main(String[] args) {

        float first = 2.60f, sec = 4.44f;

        System.out.println("--Before swapping the numbers--");
        System.out.println("First number = " + first);
        System.out.println("Second number = " + sec);

        // Value of first is assigned to temporary
        float temporary = first;

        // Value of sec is assigned to first
        first = sec;

        // Value of temporary (which contains the initial value of first) is assigned to sec 
        sec = temporary;

        System.out.println("--After swapping the numbers--");
        System.out.println("First number = " + first);
        System.out.println("Second number = " + sec);
    }
}

--Before swapping the numbers--
First number = 2.6
Second number = 4.44
--After swapping the numbers--
First number = 4.44
Second number = 2.6

first = 111, second = 222

After line 1: temporary = first

temporary = 111

After line 2: first = second

first = 222

After line 3: second = temporary

second = 222

Write a java program to compute quotient and remainder

public class QuotientRemainder {

  public static void main(String[] args) {

    int dividend = 55, divisor = 6;

    int quotient = dividend / divisor;
    int remainder = dividend % divisor;

    System.out.println("Quotient = " + quotient);
    System.out.println("Remainder = " + remainder);
  }
}

Quotient = 9
Remainder = 1

Write a java program to find ASCII value of a character

public class AsciiValue {

    public static void main(String[] args) {

        char ch = 'n';
        int ASCII = ch;
        // You can also cast char to int
        int castAscii = (int) ch;

        System.out.println("The ASCII value of " + ch + " is: " + ASCII);
        System.out.println("The ASCII value of " + ch + " is: " + castAscii);
    }
}

The ASCII value of a is: 110
The ASCII value of a is: 110

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Java program to add two Integers

class Main {

  public static void main(String[] args) {
    
    System.out.println("Enter two numbers");
    int first = 11;
    int second = 12;
    
    System.out.println(first + " " + second);

    // add two numbers
    int sum = first + second;
    System.out.println("The sum is: " + sum);
  }
}

Enter two numbers
11 12
The sum is: 23

•  Program:

import java.util.Scanner;

public class HelloWorld {

    public static void main(String[] args) {

        // Creates a reader instance which takes
        // input from standard input - keyboard
        Scanner reader = new Scanner(System.in);
        System.out.print("Enter a number: ");

        // nextInt() reads the next integer from the keyboard
        int number = reader.nextInt();

        // println() prints the following line to the output screen
        System.out.println("You entered: " + number);
    }
}

•  Output:

Enter a number: 10
You entered: 10

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•  Program:

#include <stdio.h>
int hcf(int n1, int n2);
int main() {
    int n1, n2;
    printf("Enter two positive integers: ");
    scanf("%d %d", &n1, &n2);
    printf("G.C.D of %d and %d is %d.", n1, n2, hcf(n1, n2));
    return 0;
}

int hcf(int n1, int n2) {
    if (n2 != 0)
        return hcf(n2, n1 % n2);
    else
        return n1;
}

• Output:

Enter two positive integers: 366
60
G.C.D of 366 and 60 is 6.

•  Program:

#include <math.h>
#include <stdio.h>
int main() {
    double a, b, c, discriminant, root1, root2, realPart, imagPart;
    printf("Enter coefficients a, b and c: ");
    scanf("%lf %lf %lf", &a, &b, &c);

    discriminant = b * b - 4 * a * c;

    // condition for real and different roots
    if (discriminant > 0) {
        root1 = (-b + sqrt(discriminant)) / (2 * a);
        root2 = (-b - sqrt(discriminant)) / (2 * a);
        printf("root1 = %.2lf and root2 = %.2lf", root1, root2);
    }

    // condition for real and equal roots
    else if (discriminant == 0) {
        root1 = root2 = -b / (2 * a);
        printf("root1 = root2 = %.2lf;", root1);
    }

    // if roots are not real
    else {
        realPart = -b / (2 * a);
        imagPart = sqrt(-discriminant) / (2 * a);
        printf("root1 = %.2lf+%.2lfi and root2 = %.2f-%.2fi", realPart, imagPart, realPart, imagPart);
    }

    return 0;
} 

•  Output:

Enter coefficients a, b and c: 2.3
4
5.6
root1 = -0.87+1.30i and root2 = -0.87-1.30i

1. Start
2. Input the coefficient variable, x, y and z.
3. D <- sqrt (y*y-4*x*z).
4. R1 <- (-y+D)/(2*x).
5. R2 <- (-y-D)/(2*x).
6. Print the roots R1 and R2.
7. Stop

•  Program:

#include <stdio.h>
int main() {
    FILE *fp;
    int c;
   
    // open the current input file
    fp = fopen(__FILE__,"r");

    do {
         c = getc(fp);   // read character 
         putchar(c);     // display character
    }
    while(c != EOF);  // loop until the end of file is reached
    
    fclose(fp);
    return 0;
}

•  Output:

#include <stdio.h>
int main() {
    FILE *fp;
    int c;
   
    // open the current input file
    fp = fopen(__FILE__,"r");

    do {
         c = getc(fp);   // read character 
         putchar(c);     // display character
    }
    while(c != EOF);  // loop until the end of file is reached
    
    fclose(fp);
    return 0;
}

•  Explain:

#include <stdio.h>
int main() {

   // location the current input file.
   printf("%s",__FILE__);
}

•  Steps:

1. Open the file you are currently writing using statement fopen(__FILE__,"r") and assign it to the pointer fp.
2. Scan the every character of the file and store it in the variable ch. Print it using statement putchar(ch).
3. Do step 2 until EOF(end of file).
4. Then close the file and exit.

•  Program:

#include<stdio.h>

void main()
{
    int a,b,c,d,e;
    printf("Enter the number of rows: ");
    scanf("%d",&a);
    b=a;
    for(c=1;c<=a;c++)
    {
        for(d=1;d<=b-1;d++)
        {
            printf(" ");
        }
        for(e=1;e<=2*c-1;e++)
        {
            if(e==1 || e==2*c-1 || c==a)
            {
                printf("*");
            }
            else
            {
                printf(" ");
            }
        }
        b--;
        printf("\n");
    }
}

•  Output:

Enter the number of rows: 5
    *
   * *
  *   *
 *     *
*********