Alphabet Pattern 1

/*

 * C Program to print following pattern

 *

 *      A B C D E D C B A

 *        A B C D C B A

 *          A B C B A

 *            A B A

 *              A

 *

 */

// Include

#include <stdio.h>

// Declarations

/*

 * printPattern

 * Description : Function to print pattern provided in description.

 * Parameters  : int - number of lines to be printed for given pattern.

 * Return      : void

 */

void printPattern(int i_numberOfLines);

// Definitions

int main()

{

    int i_numberOfLines = 0;

    printf("How many lines would you like to print : ");

    scanf("%d",&i_numberOfLines);

    printPattern(i_numberOfLines);

    return 0;

}

void printPattern(int i_numberOfLines)

{

    register int row, spaces, letters, noOfLetters;

    // Loop to repeat for each row

    for (row = 1; row <= i_numberOfLines; row++)

    {

        // Loop for printing spaces

        // Observe that spaces are incremental on each line.

        // row 1=0, row 2 = 1, row 3 =2 and so on.

        // So essentially number of spaces on each row is 1 less that current row.

        for (spaces = 1; spaces < row; spaces++)

        {

            printf("  ");

        }

        

        // Loop for printing incremental letters A B C D E

        // Observe that number of incremental letters are less on each row.

        // row 1 = 5, row 2 = 4, row 3 = 3 and so on.

        // So number of incremental letters on row n = Total lines - current row + 1

        noOfLetters = i_numberOfLines - row + 1;

        for (letters = 0; letters < noOfLetters; letters++)

        {

            printf("%c ", 'A'+letters);

        }

        

        // Loop for printing decremental letters D C B A

        // Observer that number of decremental letters are less on each row.

        // row 1 = 4, row 2 = 3, row 3  = 2 and so on

        // So number of decremental letters on row n = Total lines - current row.

        noOfLetters = i_numberOfLines - row;

        for (letters = noOfLetters; letters>0; letters--)

        {

            printf("%c ",'A'+letters -1);

        }

        

        // Move on to next line

        printf("\n");

    }

}

Print without semicolon

/*

 * C Program to print something without use of semicolon.

 * Trick here is  - control statements like 'if' expects expression in it.

 * The expression can be anything and we can even put printf function instead.

 */

// Include

#include <stdio.h>

int main()

{

    // No semicolon used here.

    if (printf("Gotcha !!!"))

    {

    }

}

Solve Quadratic Equation

/*

 * C Program to solve quadratic equation.

 * Quadratic Equation ->  ax^2 + bx + c = 0

 * Given - values of a, b and c.

 * We need to find out values of roots of x.

 * Formula to calculate roots of x is as follows : 

 *        

 *     

 *          

 */

// Include section

#include<stdio.h>

#include<string.h>

#include<math.h>

// Declarations

// Structure to represent roots of a quadratic equation.

typedef struct

{

    float root1;                // quadratic root 1

    float root2;                // quadratic root 2

    int   isImaginary:1;        // to represent imaginary value.

    int   errorCode;            // In case there is any problem - error code.

    char  errorDescription[50]; // Short error description.

} quadRoots;

/*

 * solveQuadraticEq

 * Description : Function to solve quadratic equation.

 * Parameters  : a, b, c values of a quadratic equation.

 * Return      : Returns quadRoots structure containing roots of a quadratic equation.

 */

quadRoots solveQuadraticEq(int a, int b, int c);

// Definitions

int main()

{

int a=0,b=0,c=0;

printf("Enter values of a,b,c in following quadratic equation :\n");

printf("ax^2 + bx + c = 0\n");

scanf("%d %d %d",&a,&b,&c);

    

    // Solve Quadratic Equation

    quadRoots result = solveQuadraticEq(a,b,c);

    if (result.errorCode != 0)  // Error occurred

    {

        printf("Error : %s\n",result.errorDescription);

    }

    else if (result.isImaginary)

    {

        // Roots are imaginary - 

        // So root 1 contains -b/2a and root 2 contains sqrt(-d)/2a

        printf("Quadratic equation %dx^2%+dx%+d = 0 has complex roots : ",a,b,c);

        printf("[ %.2f%+.2fi, %.2f%+.2fi]\n", result.root1,result.root2,result.root1,-result.root2);

    }

    else

    {

        printf("Roots of Quadratic equation %dx^2%+dx%+d = 0 are : ",a,b,c);

        printf("[ %.2f, %.2f] \n", result.root1, result.root2);

    }

return 0;

}

quadRoots solveQuadraticEq(int a, int b, int c)

{

    // Initialisations

    quadRoots roots = {0,0,0,0,""};

    float discriminant;

    

    // Value of a is 0 - meaning this is not quadratic equation.

    if (0 == a)

    {

        roots.errorCode = 1000;

        strcpy(roots.errorDescription, "Not a quadratic equation");

        return roots;

    }

    

    // discriminant = b^2 - 4*a*c

    discriminant = b*b - 4*a*c;

    

    if (discriminant == 0)      // Both roots are equal

    {

        roots.root1 = roots.root2 = -b/2.0*a;

    }

    else if (discriminant < 0)  // Roots are imaginary

    {

        roots.root1 = -b/(2.0*a);

        roots.root2 = sqrt(-discriminant)/(2.0*a);

        roots.isImaginary = 1;

    }

    else                        // Roots are real numbers

    {

        roots.root1 = (-b + sqrt(discriminant)) / (2.0*a);

        roots.root2 = (-b - sqrt(discriminant)) / (2.0*a);

    }

    return roots;

}

Star Pattern Program - 1

/*

 C Program to print following pattern.

     *         *

     * *     * *

     * * * * * *

 */

// Include Section

#include<stdio.h>

// Declarations

/* printPattern

 * Description : This function prints the pattern

 * Param         : int- number of lines to be printed.

 * Return        : void

 */

void printPattern(int);

// Definitions

int main()

{

    int i_numberOfLines = 0;

    printf("Enter how many line you want to print : ");

    scanf("%d",&i_numberOfLines);

    

    printPattern(i_numberOfLines);

}

void printPattern(int i_numberOfLines)

{

    // hItr is horizontal iterator which moves one row at a time.

    for(int hIter=0; hIter < i_numberOfLines; hIter++)

    {

        // for loop to print first number of start.

        // On every line number of stars is equal to current line number.

        for(int starIter = 0; starIter <= hIter; starIter ++)

            printf("*");

        

        // Now we have to print spaces.

        //The max number of stars that can be there is 2*number of lines.

        // On every line we print before and after spaces * equal to current line number.

        // So number of spaces to print = (2*number of lines) - (2*current Line)

        for(int spaceIter = 0; spaceIter < ((2*i_numberOfLines - 2*hIter)-1); spaceIter++)

            printf(" ");

        

        // Now print again * equal to current line number

        for(int starIter = 0; starIter <= hIter; starIter ++)

            printf("*");

        

        // Go to next line

        printf("\n");

    }

}