C Programming Language || Hands On Coding

#include <stdio.h>

int main() {
  int arr[100];
  int n, i, positiveCount = 0, negativeCount = 0;

  printf("Enter the number of elements in the array: ");
  scanf("%d", &n);

  printf("Enter the elements of the array:n");
  for (i = 0; i < n; i++) {
    scanf("%d", &arr[i]);
  }

  for (i = 0; i < n; i++) {
    if (arr[i] > 0) {
      positiveCount++;
    } else if (arr[i] < 0) {
      negativeCount++;
    }
  }

  printf("Positive numbers: %dn", positiveCount);
  printf("Negative numbers: %dn", negativeCount);

  return 0;
}

Input: 5
Input: 1
Input: -2
Input: 3
Input: -4
Input: 0
Output: Enter the number of elements in the array: Enter the elements of the array:
Positive numbers: 2
Negative numbers: 2

#include <stdio.h>

int main() {
    int arr[100];
    int n, i, evenCount = 0, oddCount = 0;

    printf("Enter the number of elements in the array: ");
    scanf("%d", &n);

    printf("Enter the elements of the array:n");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    for (i = 0; i < n; i++) {
        if (arr[i] % 2 == 0) {
            evenCount++;
        } else {
            oddCount++;
        }
    }

    printf("Even numbers: %dn", evenCount);
    printf("Odd numbers: %dn", oddCount);

    return 0;
}

Input: 5
Input: 1
Input: 2
Input: 3
Input: 4
Input: 5
Output: Even numbers: 2
Output: Odd numbers: 3

#include <stdio.h>
#include <limits.h>

int main() {
    int n, i;

    printf("Enter the number of elements in the array: ");
    scanf("%d", &n);

    int arr[n];

    printf("Enter the elements of the array:n");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    int smallest = INT_MAX;
    int secondSmallest = INT_MAX;

    for (i = 0; i < n; i++) {
        if (arr[i] < smallest) {
            secondSmallest = smallest;
            smallest = arr[i];
        } else if (arr[i] < secondSmallest && arr[i] != smallest) {
            secondSmallest = arr[i];
        }
    }

    if (secondSmallest == INT_MAX) {
        printf("There is no second smallest element.n");
    } else {
        printf("The second smallest element is: %dn", secondSmallest);
    }

    return 0;
}

Input: 5
Input: 5
Input: 2
Input: 8
Input: 1
Input: 9
Output: The second smallest element is: 2

Input: 4
Input: 1
Input: 1
Input: 1
Input: 1
Output: There is no second smallest element.

Input: 3
Input: 10
Input: 5
Input: 10
Output: The second smallest element is: 10

Input: 2
Input: 7
Input: 3
Output: The second smallest element is: 7

#include <stdio.h>

int main() {
    int n, i, largest, secondLargest;

    printf("Enter the number of elements in the array: ");
    scanf("%d", &n);

    int arr[n];

    printf("Enter the elements of the array:n");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    if (n < 2) {
        printf("Array should have at least two elements.n");
        return 0;
    }

    largest = arr[0];
    secondLargest = arr[1];

    if (secondLargest > largest) {
        int temp = largest;
        largest = secondLargest;
        secondLargest = temp;
    }

    for (i = 2; i < n; i++) {
        if (arr[i] > largest) {
            secondLargest = largest;
            largest = arr[i];
        } else if (arr[i] > secondLargest && arr[i] != largest) {
            secondLargest = arr[i];
        }
    }

    if (largest == secondLargest) {
        printf("There is no second largest element as all elements are the same.n");
    } else {
        printf("The second largest element in the array is: %dn", secondLargest);
    }

    return 0;
}

Input: 5
Input: 10
Input: 5
Input: 8
Input: 2
Input: 7
Output: The second largest element in the array is: 8

Input: 3
Input: 5
Input: 5
Input: 5
Output: There is no second largest element as all elements are the same.

Input: 1
Output: Enter the number of elements in the array: Array should have at least two elements.

Input: 2
Input: 1
Input: 2
Output: The second largest element in the array is: 1

#include <stdio.h>

int main() {
    int n;
    printf("Enter the number of elements: ");
    scanf("%d", &n);

    int arr[n];
    printf("Enter the elements:n");
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    int uniqueArr[n];
    int uniqueSize = 0;

    for (int i = 0; i < n; i++) {
        int isDuplicate = 0;
        for (int j = 0; j < uniqueSize; j++) {
            if (arr[i] == uniqueArr[j]) {
                isDuplicate = 1;
                break;
            }
        }
        if (!isDuplicate) {
            uniqueArr[uniqueSize] = arr[i];
            uniqueSize++;
        }
    }

    printf("Array with unique elements:n");
    for (int i = 0; i < uniqueSize; i++) {
        printf("%d ", uniqueArr[i]);
    }
    printf("n");

    return 0;
}

Input: 5
Input: 1
Input: 2
Input: 2
Input: 3
Input: 4
Output: Enter the number of elements: Enter the elements:
Array with unique elements:
1 2 3 4
Input: 7
Input: 5
Input: 2
Input: 5
Input: 1
Input: 2
Input: 3
Input: 4
Output: Enter the number of elements: Enter the elements:
Array with unique elements:
5 2 1 3 4

#include <stdio.h>
#include <stdbool.h>

int main() {
    int n;

    printf("Enter the size of the array: ");
    scanf("%d", &n);

    int arr[n];

    printf("Enter the elements of the array: ");
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    bool isSorted = true;
    for (int i = 0; i < n - 1; i++) {
        if (arr[i] > arr[i + 1]) {
            isSorted = false;
            break;
        }
    }

    if (isSorted) {
        printf("Array is sorted.n");
    } else {
        printf("Array is not sorted.n");
    }

    return 0;
}

Input: 5
Input: 1 2 3 4 5
Output: Array is sorted.
Input: 5
Input: 5 4 3 2 1
Output: Array is not sorted.
Input: 4
Input: 1 2 4 3
Output: Array is not sorted.
Input: 3
Input: 1 1 1
Output: Array is sorted.
Input: 1
Input: 10
Output: Array is sorted.

#include <stdio.h>

int main() {
    int n, i, temp;

    printf("Enter the number of elements in the array: ");
    scanf("%d", &n);

    int arr[n];

    printf("Enter the elements of the array:n");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    // Reversing the array
    for (i = 0; i < n / 2; i++) {
        temp = arr[i];
        arr[i] = arr[n - i - 1];
        arr[n - i - 1] = temp;
    }

    printf("Reversed array: ");
    for (i = 0; i < n; i++) {
        printf("%d ", arr[i]);
    }
    printf("n");

    return 0;
}

Input: 5
Input: 1
Input: 2
Input: 3
Input: 4
Input: 5
Output: Enter the number of elements in the array: Enter the elements of the array:
Reversed array: 5 4 3 2 1

Input: 6
Input: 10
Input: 20
Input: 30
Input: 40
Input: 50
Input: 60
Output: Enter the number of elements in the array: Enter the elements of the array:
Reversed array: 60 50 40 30 20 10

#include <stdio.h>

int main() {
  int n, i;
  float sum = 0.0, average;

  printf("Enter the number of elements: ");
  scanf("%d", &n);

  float arr[n];

  printf("Enter the elements:n");
  for (i = 0; i < n; i++) {
    scanf("%f", &arr[i]);
    sum += arr[i];
  }

  average = sum / n;

  printf("Average = %.2fn", average);

  return 0;
}

Input: 3
Input: 1.0
Input: 2.0
Input: 3.0
Output: Enter the number of elements: Enter the elements:
Average = 2.00

#include <stdio.h>

int main() {
    int n, i, sum = 0;

    printf("Enter the number of elements in the array: ");
    scanf("%d", &n);

    int arr[n];

    printf("Enter the elements of the array:n");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    for (i = 0; i < n; i++) {
        sum += arr[i];
    }

    printf("Sum of all elements in the array = %dn", sum);

    return 0;
}

Input: 5
Input: 1
Input: 2
Input: 3
Input: 4
Input: 5
Output: Enter the number of elements in the array: Enter the elements of the array:
Sum of all elements in the array = 15

#include <stdio.h>

int main() {
  int arr[5];
  int smallest;
  int i;

  printf("Enter 5 integer elements:n");
  for (i = 0; i < 5; i++) {
    scanf("%d", &arr[i]);
  }

  smallest = arr[0];

  for (i = 1; i < 5; i++) {
    if (arr[i] < smallest) {
      smallest = arr[i];
    }
  }

  printf("Smallest element: %dn", smallest);

  return 0;
}

Input: 5
Input: 2
Input: 8
Input: 1
Input: 9
Output: Enter 5 integer elements:
Output: Smallest element: 1

#include <stdio.h>

int main() {
    int n;
    printf("Enter the number of elements in the array: ");
    scanf("%d", &n);

    int arr[n];
    printf("Enter the elements of the array:n");
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    int largest = arr[0];
    for (int i = 1; i < n; i++) {
        if (arr[i] > largest) {
            largest = arr[i];
        }
    }

    printf("The largest element in the array is: %dn", largest);

    return 0;
}

Input: 5
Input: 12
Input: 5
Input: 28
Input: 3
Input: 19
Output: Enter the number of elements in the array: Enter the elements of the array:
The largest element in the array is: 28

#include <stdio.h>

int sum_natural(int n) {
    if (n == 0) {
        return 0;
    } else {
        return n + sum_natural(n - 1);
    }
}

int main() {
    int num;

    printf("Enter a positive integer: ");
    scanf("%d", &num);

    if (num < 0) {
        printf("Please enter a non-negative integer.n");
    } else {
        int sum = sum_natural(num);
        printf("Sum of natural numbers up to %d = %dn", num, sum);
    }

    return 0;
}

Input: 5
Output: Enter a positive integer: Sum of natural numbers up to 5 = 15

Input: 0
Output: Enter a positive integer: Sum of natural numbers up to 0 = 0

Input: -3
Output: Enter a positive integer: Please enter a non-negative integer.

#include <stdio.h>

void increment(int *n) {
  *n = *n + 1;
}

int main() {
  int num = 10;
  printf("Before increment: %dn", num);
  increment(&num);
  printf("After increment: %dn", num);
  return 0;
}

Before increment: 10
After increment: 11

#include <stdio.h>

void modifyValue(int x) {
  x = x + 10;
  printf("Value inside function: %dn", x);
}

int main() {
  int num;

  printf("Enter an integer: ");
  scanf("%d", &num);

  printf("Value before function call: %dn", num);
  modifyValue(num);
  printf("Value after function call: %dn", num);

  return 0;
}

Input: 5
Output: Enter an integer: Value before function call: 5
Value inside function: 15
Value after function call: 5

#include <stdio.h>

int factorial(int n) {
    int fact = 1;
    for (int i = 1; i <= n; i++) {
        fact *= i;
    }
    return fact;
}

int isStrong(int num) {
    int originalNum = num;
    int sum = 0;
    while (num > 0) {
        int digit = num % 10;
        sum += factorial(digit);
        num /= 10;
    }
    if (sum == originalNum) {
        return 1;
    } else {
        return 0;
    }
}

int main() {
    int number;
    printf("Enter a number: ");
    scanf("%d", &number);

    if (isStrong(number)) {
        printf("%d is a strong number.n", number);
    } else {
        printf("%d is not a strong number.n", number);
    }

    return 0;
}

Input: 145
Output: 145 is a strong number.

Input: 123
Output: 123 is not a strong number.

Input: 40585
Output: 40585 is a strong number.

#include <stdio.h>

int isPerfect(int num) {
    int sum = 1;
    for (int i = 2; i * i <= num; i++) {
        if (num % i == 0) {
            if (i * i != num)
                sum = sum + i + num / i;
            else
                sum = sum + i;
        }
    }
    if (sum == num && num != 1)
        return 1; // True
    else
        return 0; // False
}

int main() {
    int number;
    printf("Enter a number: ");
    scanf("%d", &number);

    if (isPerfect(number)) {
        printf("%d is a perfect numbern", number);
    } else {
        printf("%d is not a perfect numbern", number);
    }

    return 0;
}

Input: 6
Output: 6 is a perfect number

Input: 28
Output: 28 is a perfect number

Input: 12
Output: 12 is not a perfect number

Input: 496
Output: 496 is a perfect number

Input: 8128
Output: 8128 is a perfect number

Input: 1
Output: 1 is not a perfect number

Input: 0
Output: 0 is not a perfect number

Input: -1
Output: -1 is not a perfect number

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

int binaryToDecimal(long long n) {
    int decimalNumber = 0, i = 0, remainder;
    while (n!=0) {
        remainder = n % 10;
        n /= 10;
        decimalNumber += remainder * pow(2, i);
        ++i;
    }
    return decimalNumber;
}

int main() {
    long long n;
    printf("Enter a binary number: ");
    scanf("%lld", &n);
    printf("Decimal equivalent: %d", binaryToDecimal(n));
    return 0;
}

Input: 101101
Output: Decimal equivalent: 45
Input: 1111
Output: Decimal equivalent: 15
Input: 0
Output: Decimal equivalent: 0
Input: 10000000
Output: Decimal equivalent: 128
Input: 1
Output: Decimal equivalent: 1

#include <stdio.h>
#include <stdlib.h>

void decimalToBinary(int n) {
  if (n > 0) {
    decimalToBinary(n / 2);
    printf("%d", n % 2);
  }
}

int main() {
  int decimal;

  printf("Enter a decimal number: ");
  scanf("%d", &decimal);

  printf("Binary equivalent: ");
  if(decimal == 0){
      printf("0");
  } else {
      decimalToBinary(decimal);
  }
  printf("n");

  return 0;
}

Input: 10
Output: Enter a decimal number: Binary equivalent: 1010
Input: 0
Output: Enter a decimal number: Binary equivalent: 0
Input: 25
Output: Enter a decimal number: Binary equivalent: 11001
Input: 128
Output: Enter a decimal number: Binary equivalent: 10000000
Input: 1
Output: Enter a decimal number: Binary equivalent: 1

#include <stdio.h>

int sumOfDigits(int num) {
    int sum = 0;
    while (num != 0) {
        sum += num % 10;
        num /= 10;
    }
    return sum;
}

int main() {
    int number;
    printf("Enter a positive integer: ");
    scanf("%d", &number);

    if (number < 0) {
        printf("Please enter a positive integer.n");
        return 1;
    }

    int sum = sumOfDigits(number);
    printf("Sum of digits of %d is %dn", number, sum);

    return 0;
}

Input: 12345
Output: Enter a positive integer: Sum of digits of 12345 is 15

Input: 5
Output: Enter a positive integer: Sum of digits of 5 is 5

Input: 999
Output: Enter a positive integer: Sum of digits of 999 is 27

Input: -10
Output: Enter a positive integer: Please enter a positive integer.