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C Coding Questions

  • Write a C program to find the sum of two integers.
c
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#include <stdio.h>

int main() {
    int a, b, sum;
    printf("Enter two integers: ");
    scanf("%d %d", &a, &b);
    sum = a + b;
    printf("Sum of %d and %d is %d\n", a, b, sum);
    return 0;
}
  • Write a C program to find the factorial of a number.
c
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#include <stdio.h>

int main() {
    int n, i, factorial = 1;
    printf("Enter a positive integer: ");
    scanf("%d", &n);
    for (i = 1; i <= n; i++) {
        factorial *= i;
    }
    printf("Factorial of %d is %d\n", n, factorial);
    return 0;
}
  • Write a C program to find the largest among three numbers.
c
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#include <stdio.h>

int main() {
    int a, b, c, largest;
    printf("Enter three numbers: ");
    scanf("%d %d %d", &a, &b, &c);
    if (a > b && a > c) {
        largest = a;
    } else if (b > a && b > c) {
        largest = b;
    } else {
        largest = c;
    }
    printf("Largest among %d, %d and %d is %d\n", a, b, c, largest);
    return 0;
}
  • Write a C program to find the sum of numbers from 1 to n.
c
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#include <stdio.h>

int main() {
    int n, i, sum = 0;
    printf("Enter a positive integer: ");
    scanf("%d", &n);
    for (i = 1; i <= n; i++) {
        sum += i;
    }
    printf("Sum of numbers from 1 to %d is %d\n", n, sum);
    return 0;
}
  • Write a C program to swap two numbers without using a temporary variable.
c
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#include <stdio.h>

int main() {
    int a, b;
    printf("Enter two numbers: ");
    scanf("%d %d", &a, &b);
    a = a + b;
    b = a - b;
    a = a - b;
    printf("After swapping, a = %d and b = %d\n", a, b);
    return 0;
}
  • Write a C program to reverse a string.
c
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#include <stdio.h>
#include <string.h>

int main() {
    char str[100], temp;
    int i, j;
    printf("Enter a string: ");
    scanf("%s", str);
    j = strlen(str) - 1;
    for (i = 0; i < j; i++, j--) {
        temp = str[i];
        str[i] = str[j];
        str[j] = temp;
    }
    printf("Reversed string is: %s\n", str);
    return 0;
}
  • Write a C program to find the second largest number in an array.
c
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#include <stdio.h>

int main() {
    int n, i, largest, second_largest;
    printf("Enter the size of the array: ");
    scanf("%d", &n);
    int arr[n];
    printf("Enter the elements of the array: ");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }
    largest = arr[0];
    second_largest = arr[1];
    for (i = 1; i < n; i++) {
        if (arr[i] > largest) {
            second_largest = largest;
            largest = arr[i];
        } else if (arr[i] > second_largest && arr[i] != largest) {
            second_largest = arr[i];
        }
    }
    printf("The second largest element in the array is: %d\n", second_largest);
    return 0;
}
  • Write a C program to count the number of even and odd elements in an array.
c
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#include <stdio.h>

int main() {
    int n, i, even_count = 0, odd_count = 0;
    printf("Enter the size of the array: ");
    scanf("%d", &n);
    int arr[n];
    printf("Enter the elements of the array: ");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
        if (arr[i] % 2 == 0) {
            even_count++;
        } else {
            odd_count++;
        }
    }
    printf("The number of even elements in the array is: %d\n", even_count);
    printf("The number of odd elements in the array is: %d\n", odd_count);
    return 0;
}
  • Write a C program to reverse an array.
c
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#include <stdio.h>

int main() {
    int n, i, j, temp;
    printf("Enter the size of the array: ");
    scanf("%d", &n);
    int arr[n];
    printf("Enter the elements of the array: ");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }
    j = n - 1;
    for (i = 0; i < j; i++, j--) {
        temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
    printf("The reversed array is: ");
    for (i = 0; i < n; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");
    return 0;
}
  • Write a C program to check if a given string is a palindrome or not.
c
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#include <stdio.h>
#include <string.h>

int main() {
    char str[100];
    int i, j, n, flag = 0;
    printf("Enter a string: ");
    scanf("%s", str);
    n = strlen(str);
    for (i = 0, j = n - 1; i < j; i++, j--) {
        if (str[i] != str[j]) {
            flag = 1;
            break;
        }
    }
    if (flag == 0) {
        printf("%s is a palindrome.\n", str);
    } else {
        printf("%s is not a palindrome.\n", str);
    }
    return 0;
}
  • Write a C program to find the sum of all elements in an array.
c
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#include <stdio.h>

int main() {
    int n, i, sum = 0;
    printf("Enter the size of the array: ");
    scanf("%d", &n);
    int arr[n];
    printf("Enter the elements of the array: ");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
        sum += arr[i];
    }
    printf("The sum of all elements in the array is: %d\n", sum);
    return 0;
}
  • Write a C program to find the frequency of a given element in an array.
c
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#include <stdio.h>

int main() {
    int n, i, element, frequency = 0;
    printf("Enter the size of the array: ");
    scanf("%d", &n);
    int arr[n];
    printf("Enter the elements of the array: ");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }
    printf("Enter the element to find its frequency: ");
    scanf("%d", &element);
    for (i = 0; i < n; i++) {
        if (arr[i] == element) {
            frequency++;
        }
    }
    printf("The frequency of %d in the array is: %d\n", element, frequency);
    return 0;
}
  • Write a C program to remove duplicates from an array.
c
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#include <stdio.h>

int main() {
    int n, i, j, k;
    printf("Enter the size of the array: ");
    scanf("%d", &n);
    int arr[n];
    printf("Enter the elements of the array: ");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }
    for (i = 0; i < n; i++) {
        for (j = i + 1; j < n; j++) {
            if (arr[i] == arr[j]) {
                for (k = j; k < n; k++) {
                    arr[k] = arr[k + 1];
                }
                n--;
                j--;
            }
        }
    }
    printf("The array with duplicates removed is: ");
    for (i = 0; i < n; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");
    return 0;
}
  • Write a C program to reverse a given string without using the built-in strrev() function.
c
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#include <stdio.h>
#include <string.h>

int main() {
    char str[100], temp;
    int i, j, n;
    printf("Enter a string: ");
    scanf("%s", str);
    n = strlen(str);
    for (i = 0, j = n - 1; i < j; i++, j--) {
        temp = str[i];
        str[i] = str[j];
        str[j] = temp;
    }
    printf("The reversed string is: %s\n", str);
    return 0;
}
  • Write a C program to find the largest and smallest element in an array.
c
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#include <stdio.h>

int main() {
    int n, i, max, min;
    printf("Enter the size of the array: ");
    scanf("%d", &n);
    int arr[n];
    printf("Enter the elements of the array: ");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }
    max = min = arr[0];
    for (i = 1; i < n; i++) {
        if (arr[i] > max) {
            max = arr[i];
        }
        if (arr[i] < min) {
            min = arr[i];
        }
    }
    printf("The largest element in the array is: %d\n", max);
    printf("The smallest element in the array is: %d\n", min);
    return 0;
}
  • Write a C program to find the second largest element in an array.
c
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#include <stdio.h>

int main() {
    int n, i, largest, second_largest;
    printf("Enter the size of the array: ");
    scanf("%d", &n);
    int arr[n];
    printf("Enter the elements of the array: ");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }
    largest = second_largest = arr[0];
    for (i = 1; i < n; i++) {
        if (arr[i] > largest) {
            second_largest = largest;
            largest = arr[i];
        } else if (arr[i] > second_largest && arr[i] != largest) {
            second_largest = arr[i];
        }
    }
    printf("The second largest element in the array is: %d\n", second_largest);
    return 0;
}
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