C Programs on Flow Control

C Program to Check Whether a Character is a Vowel or Consonant

Code:

#include <stdio.h>
int main()
{
    char c;
    int low, upp;
    printf("Enter any alphabet: ");
    scanf("%c", &c);
    low = (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u');
    upp = (c == 'A' || c == 'E' || c == 'I' || c == 'O' || c == 'U');
    if (low || upp)
    {
        printf("Vowel\n");
    }
    else
    {
        printf("Consonant\n");
    }
    return 0;
}

Output:

Enter any alphabet: A
Vowel

C Program to Find the Largest Number Among Three Numbers

Code:

#include <stdio.h>
int main()
{
    int a, b, c;
    printf("Enter first no: ");
    scanf("%d", &a);
    printf("Enter second no: ");
    scanf("%d", &b);
    printf("Enter third no: ");
    scanf("%d", &c);
    if (a >= b && a >= c)
        printf("Largest number: %d\n", a);
    if (b >= a && b >= c)
        printf("Largest number: %d\n", b);
    if (c >= a && c >= b)
        printf("Largest number is %d\n", c);
    return 0;
}

Output:

Enter first no: 1
Enter second no: 6
Enter third no: 4
Largest number: 6

C Program to Find the Roots of a Quadratic Equation

Code:

#include <math.h>
#include <stdio.h>
int main()
{
    double a, b, c, disc, rt1, rt2, real, imaginary;
    printf("Enter coefficients a: ");
    scanf("%lf", &a);
    printf("Enter coefficients b: ");
    scanf("%lf", &b);
    printf("Enter coefficients c: ");
    scanf("%lf", &c);

    disc = (b * b) - (4 * a * c);
    if (disc > 0)
    {
        rt1 = (-b + sqrt(disc)) / (2 * a);
        rt2 = (-b - sqrt(disc)) / (2 * a);
        printf("rt1 = %.2lf and rt2 = %.2lf", rt1, rt2);
    }
    else if (disc == 0)
    {
        rt1 = rt2 = -b / (2 * a);
        printf("First root = Second root = %.2lf;", rt1);
    }
    else
    {
        real = -b / (2 * a);
        imaginary = sqrt(-disc) / (2 * a);
        printf("First root = %.2lf+%.2lfi and Second root = %.2f-%.2fi", real, imaginary, real, imaginary);
    }
    return 0;
}

Output:

Enter coefficients a: 4
Enter coefficients b: 5
Enter coefficients c: 2
First root = -0.62+0.33i and Second root = -0.62-0.33i

C Program to Check Leap Year

Code:

#include <stdio.h>
int main()
{
    int n;
    printf("Year: ");
    scanf("%d", &n);
    if (n % 400 == 0)
    {
        printf("Leap Year", n);
    }
    else if (n % 100 == 0)
    {
        printf("Not a Leap Year", n);
    }
    else if (n % 4 == 0)
    {
        printf("Leap Year", n);
    }
    else
    {
        printf("Not a Leap Year", n);
    }
    return 0;
}

Output:

Year: 2020
Leap Year

C Program to Check Whether a Number is Positive or Negative

Code:

#include <stdio.h>
int main()
{
    int n;
    printf("Input a number: ");
    scanf("%d", &n);
    if (n <= 0.0)
    {
        if (n == 0.0)
            printf("Entered number is 0\n");
        else
            printf("Negative number\n");
    }
    else
        printf("Positive number\n");
    return 0;
}

Output:

Input a number: 5
Positive number

C Program to Check Whether a Character is an Alphabet or not

Code:

#include <stdio.h>
int main()
{
    char val;
    printf("Enter a character value: ");
    scanf("%c", &val);

    if ((val >= 'a' && val <= 'z') || (val >= 'A' && val <= 'Z'))
        printf("Alphabet\n", val);
    else
        printf("Not an alphabet\n", val);

    return 0;
}

Output:

Enter a character value: b
Alphabet

C Program to Calculate the Sum of Natural Numbers

Code:

#include <stdio.h>
int main()
{
    int n, i, add = 0;
    printf("Enter a number: ");
    scanf("%d", &n);
    for (i = 1; i <= n; ++i)
    {
        add = add+i;
    }
    printf("Sum of natural numbers from 1 to %d is %d\n", n, add);
    return 0;
}

Output:

Enter a number: 8
Sum of natural numbers from 1 to 8 is 36

C Program to Find Factorial of a Number

Code:

#include <stdio.h>
int main()
{
    int num, i;
    long long unsigned int fact = 1;
    printf("Enter a number: ");
    scanf("%d", &num);
    if (num < 0)
        printf("Write a positive number.");
    else
    {
        for (i = 1; i <= num; ++i)
        {
            fact *= i;
        }
        printf("Factorial is %llu\n", fact);
    }

    return 0;
}

Output:

Enter a number: 5
Factorial is 120

C Program to Generate Multiplication Table

Code:

#include <stdio.h>
int main()
{
    int a, i;
    printf("Enter an integer value: ");
    scanf("%d", &a);
    for (i = 1; i <= 10; ++i)
    {
        printf("%d * %d = %d \n", a, i, a * i);
    }
    return 0;
}

Output:

Enter an integer value: 9
9 * 1 = 9 
9 * 2 = 18 
9 * 3 = 27 
9 * 4 = 36 
9 * 5 = 45 
9 * 6 = 54 
9 * 7 = 63 
9 * 8 = 72 
9 * 9 = 81 
9 * 10 = 90

C Program to Display Fibonacci Sequence

Code:

#include <stdio.h>
int main()
{
    int i, n, term1 = 0, term2 = 1, next;
    printf("Number of terms to be calculated: ");
    scanf("%d", &n);
    printf("This is the Fibonacci Series: ");

    for (i = 1; i <= n; ++i)
    {
        printf("%d, ", term1);
        next = term1 + term2;
        term1 = term2;
        term2 = next;
    }
    printf("\n");
    return 0;
}

Output:

Number of terms to be calculated: 8
This is the Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13,

C Program to Find GCD of two Numbers

Code:

#include <stdio.h>
int main()
{
    int number1, number2, i, GCD;
    printf("Enter first integer: ");
    scanf("%d", &number1);
    printf("Enter two integer: ");
    scanf("%d", &number2);
    for (i = 1; i <= number1 && i <= number2; ++i)
    {
        if (number1 % i == 0 && number2 % i == 0)
            GCD = i;
    }
    printf("G.C.D: %d\n", GCD);
    return 0;
}

Output:

Enter first integer: 5
Enter two integer: 9
G.C.D: 1

C Program to Find LCM of two Numbers

Code:

#include <stdio.h>
int main()
{
    int number1, number2, maximum;
    printf("Enter first integer: ");
    scanf("%d", &number1);
    printf("Enter second integer: ");
    scanf("%d", &number2);
    maximum = (number1 > number2) ? number1 : number2;
    while (1)
    {
        if (maximum % number1 == 0 && maximum % number2 == 0)
        {
            printf("LCM: %d\n", maximum);
            break;
        }
        ++maximum;
    }
    return 0;
}

Output:

Enter first integer: 10
Enter second integer: 20
LCM: 20

C Program to Display Characters from A to Z Using Loop

Code:

#include <stdio.h>
int main()
{
    char ch;
    for (ch = 'A'; ch <= 'Z'; ++ch)
    {
        printf("%c ", ch);
    }
    printf("\n");       
    return 0;
}

Output:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

C Program to Count Number of Digits in an Integer

Code:

#include <stdio.h>
int main()
{
    long long a;
    int count = 0;
    printf("Enter an integer value: ");
    scanf("%lld", &a);
    while (a != 0)
    {
        a /= 10;
        ++count;
    }
    printf("%d digits in integer\n", count);
}

Output:

Enter an integer value: 145
3 digits in integer

C Program to Reverse a Number

Code:

#include <stdio.h>
int main()
{
    int n, reverse = 0, rem;
    printf("Enter an integer value: ");
    scanf("%d", &n);
    while (n != 0)
    {
        rem = n % 10;
        reverse = reverse * 10 + rem;
        n /= 10;
    }
    printf("Reverse of the number is %d\n", reverse);
    return 0;
}

Output:

Enter an integer value: 1984
Reverse of the number is 4891

C Program to Calculate the Power of a Number

Code:

#include <stdio.h>
int main()
{
    int a, n;
    long long sum = 1;
    printf("Base number: ");
    scanf("%d", &a);
    printf("Exponent: ");
    scanf("%d", &n);
    while (n != 0)
    {
        sum *= a;
        --n;
    }
    printf("Value evaluated is %lld\n", sum);
    return 0;
}

Output:

Base number: 8
Exponent: 3
Value evaluated is 512

C Program to Check Whether a Number is Palindrome or Not

Code:

#include <stdio.h>
int main()
{
    int n, reverse = 0, rem, origin;
    printf("Enter an integer value : ");
    scanf("%d", &n);
    origin = n;
    while (n != 0)
    {
        rem = n % 10;
        reverse = reverse * 10 + rem;
        n /= 10;
    }
    if (origin == reverse)
        printf("Palindrome\n", origin);
    else
        printf("Not a Palindrome\n", origin);

    return 0;
}

Output:

Enter an integer value : 5       
Palindrome

C Program to Check Whether a Number is Prime or Not

Code:

#include <stdio.h>
int main()
{
    int num, i, k = 0;
    printf("Enter a number: ");
    scanf("%d", &num);
    for (i = 2; i <= num / 2; ++i)
    {
        if (num % i == 0)
        {
            k = 1;
            break;
        }
    }
    if (k == 0)
        printf("Prime number\n", num);
    else
        printf("Not a Prime number\n", num);
    return 0;
}

Output:

Enter a number: 49
Not a Prime number

C Program to Display Prime Numbers Between Two Intervals

Code:

#include <stdio.h>
int main()
{
    int open, close, i, k;
    printf("Enter opening intervals: ");
    scanf("%d", &open);
    printf("Enter closing intervals: ");
    scanf("%d",&close);
    printf("Prime number are ", open, close);
    while (open < close)
    {
        k = 0;
        if (open <= 1)
        {
            ++open;
            continue;
        }
        for (i = 2; i <= open / 2; ++i)
        {

            if (open % i == 0)
            {
                k = 1;
                break;
            }
        }
        if (k == 0)
            printf("%d ", open);
        ++open;
    }
    printf("\n");
    return 0;
}

Output:

Enter opening intervals: 1
Enter closing intervals: 20
Prime number are 2 3 5 7 11 13 17 19

C Program to Check Armstrong Number

Code:

#include <math.h>
#include <stdio.h>

int main()
{
   int number, original, rem, n = 0;
   float result = 0.0;
   printf("Enter an number: ");
   scanf("%d", &number);
   original = number;
   for (original = number; original != 0; ++n)
   {
       original /= 10;
   }
   for (original = number; original != 0; original /= 10)
   {
       rem = original % 10;
      result += pow(rem, n);
   }
   if ((int)result == number)
    printf("Armstrong number\n", number);
   else
    printf("Armstrong number\n", number);
   return 0;
}

Output:

Enter an number: 9
Armstrong number

C Program to Display Armstrong Number Between Two Intervals

Code:

#include <math.h>
#include <stdio.h>
int main()
{
    int lowest, highest, number, original, remainder, reps = 0;
    double result = 0.0;
    printf("Enter opening interval: ");
    scanf("%d", &lowest);
    printf("Enter closing interval: ");
    scanf("%d", &highest);
    printf("Armstrong numbers are: ", lowest, highest);
    for (number = lowest + 1; number < highest; ++number)
    {
        original = number;
        while (original != 0)
        {
            original /= 10;
            ++reps;
        }
        original = number;
        while (original != 0)
        {
            remainder = original % 10;
            result += pow(remainder, reps);
            original /= 10;
        }
        if ((int)result == number)
        {
            printf("%d ", number);
        }
        reps = 0;
        result = 0;
    }
    printf("\n");
    return 0;
}

Output:

Enter opening interval: 5
Enter closing interval: 20
Armstrong numbers are: 6 7 8 9

C Program to Display Factors of a Number

Code:

#include <stdio.h>
int main()
{
    int number, i;
    printf("Enter an integer: ");
    scanf("%d", &number);
    printf("Factors: ", number);
    for (i = 1; i <= number; ++i)
    {
        if (number % i == 0)
        {
            printf("%d ", i);
        }
    }
    printf("\n");
    return 0;
}

Output:

Enter an integer: 5
Factors: 1 5

C Program to Make a Simple Calculator Using switch…case

Code:

#include <stdio.h>
int main()
{
    char oprtr;
    double n1, n2;
    printf("Enter an operation to be done (+, -, *,): ");
    scanf("%c", &oprtr);
    printf("Enter first number: ");
    scanf("%lf", &n1);
    printf("Enter second number: ");
    scanf("%lf", &n2);
    switch (oprtr)
    {
    case '+':
        printf("%.1lf + %.1lf = %.1lf", n1, n2, n1 + n2);
        break;
    case '-':
        printf("%.1lf - %.1lf = %.1lf", n1, n2, n1 - n2);
        break;
    case '*':
        printf("%.1lf * %.1lf = %.1lf", n1, n2, n1 * n2);
        break;
    case '/':
        printf("%.1lf / %.1lf = %.1lf", n1, n2, n1 / n2);
        break;
    default:
        printf(" oprtr is not correct");
    }
    printf("\n");
    return 0;
}

Output:

Enter an operation to be done (+, -, *,): +
Enter first number: 4
Enter second number: 6
4.0 + 6.0 = 10.0