C program to check whether a number is prime or not

PROGRAM:

#include <stdio.h>
int main()
{
    int n, i, flag = 0;

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

    for(i=2; i<=n/2; ++i)
    {
        
        if(n%i==0)
        {
            flag=1;
            break;
        }
    }

    if (flag==0)
        printf("%d is a prime number.",n);
    else
        printf("%d is not a prime number.",n);
    
    return 0;
}

OUTPUT:

Enter a positive integer: 29
29 is a prime number.

C program to make a simple calculator using switch...case

PROGRAM:

# include <stdio.h>

int main() {

    char operator;
    double firstNumber,secondNumber;

    printf("Enter an operator (+, -, *,): ");
    scanf("%c", &operator);

    printf("Enter two operands: ");
    scanf("%lf %lf",&firstNumber, &secondNumber);

    switch(operator)
    {
        case '+':
            printf("%.1lf + %.1lf = %.1lf",firstNumber, secondNumber, firstNumber + secondNumber);
            break;

        case '-':
            printf("%.1lf - %.1lf = %.1lf",firstNumber, secondNumber, firstNumber - secondNumber);
            break;

        case '*':
            printf("%.1lf * %.1lf = %.1lf",firstNumber, secondNumber, firstNumber * secondNumber);
            break;

        case '/':
            printf("%.1lf / %.1lf = %.1lf",firstNumber, secondNumber, firstNumber / secondNumber);
            break;

        
        default:
            printf("Error! operator is not correct");
    }
    
    return 0;
}

OUTPUT:

Enter an operator (+, -, *,): *
Enter two operands: 1.5
4.5
1.5 * 4.5 = 6.8

C program to display factors of a number

PROGRAM:

#include <stdio.h>
int main()
{
    int number, i;

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

    printf("Factors of %d are: ", number);
    for(i=1; i <= number; ++i)
    {
        if (number%i == 0)
        {
            printf("%d ",i);
        }
    }

    return 0;
}

OUTPUT:

Enter a positive integer: 60
Factors of 60 are: 1 2 3 4 5 6 10 12 15 20 30 60

C program to display Armstrong number between two intervals

PROGRAM:

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

int main()
{
    int low, high, i, temp1, temp2, remainder, n = 0, result = 0;

    printf("Enter two numbers(intervals): ");
    scanf("%d %d", &low, &high);
    printf("Armstrong numbers between %d an %d are: ", low, high);

    for(i = low + 1; i < high; ++i)
    {
        temp2 = i;
        temp1 = i;

        while (temp1 != 0)
        {
            temp1 /= 10;
            ++n;
        }

      
        while (temp2 != 0)
        {
            remainder = temp2 % 10;
            result += pow(remainder, n);
            temp2 /= 10;
        }

     
        if (result == i) {
            printf("%d ", i);
        }

         
        n = 0;
        result = 0;

    }
    return 0;
}

OUTPUT:

Enter two numbers(intervals): 999
99999
Armstrong numbers between 999 an 99999 are: 1634 8208 9474 54748 92727 93084

C program to check Armstrong number

PROGRAM-1:

Check Armstrong number of three digits

#include <stdio.h>
int main()
{
    int number, originalNumber, remainder, result = 0;

    printf("Enter a three digit integer: ");
    scanf("%d", &number);

    originalNumber = number;

    while (originalNumber != 0)
    {
        remainder = originalNumber%10;
        result += remainder*remainder*remainder;
        originalNumber /= 10;
    }

    if(result == number)
        printf("%d is an Armstrong number.",number);
    else
        printf("%d is not an Armstrong number.",number);

    return 0;
}

OUTPUT:

Enter a three digit integer: 371
371 is an Armstrong number.

PROGRAM-2:

Check Armstrong number of n digits

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

int main()
{
    int number, originalNumber, remainder, result = 0, n = 0 ;

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

     originalNumber = number;
    
    while (originalNumber != 0)
    {
        originalNumber /= 10;
        ++n;
    }

    originalNumber = number;

    while (originalNumber != 0)
    {
        remainder = originalNumber%10;
        result += pow(remainder, n);
        originalNumber /= 10;
    }

    if(result == number)
        printf("%d is an Armstrong number.", number);
    else
        printf("%d is not an Armstrong number.", number);

    return 0;
}

OUTPUT:

Enter an integer: 1634
1634 is an Armstrong number.

C program to display prime numbers between two intervals

PROGRAM-1:

#include <stdio.h>
int main()
{
    int low, high, i, flag;
    printf("Enter two numbers(intervals): ");
    scanf("%d %d", &low, &high);

    printf("Prime numbers between %d and %d are: ", low, high);

    while (low < high)
    {
        flag = 0;

        for(i = 2; i <= low/2; ++i)
        {
            if(low % i == 0)
            {
                flag = 1;
                break;
            }
        }

        if (flag == 0)
            printf("%d ", low);

        ++low;
    }

    return 0;
}

OUTPUT:

Enter two numbers(intervals): 20 
50
Prime numbers between 20 and 50 are: 23 29 31 37 41 43 47

PROGRAM-2:

#include <stdio.h>
int main()
{
    int low, high, i, flag, temp;
    printf("Enter two numbers(intevals): ");
    scanf("%d %d", &low, &high);

    
    if (low > high) {
        temp = low;
        low = high;
        high = temp;
    }

    printf("Prime numbers between %d and %d are: ", low, high);

    while (low < high)
    {
        flag = 0;

        for(i = 2; i <= low/2; ++i)
        {
            if(low % i == 0)
            {
                flag = 1;
                break;
            }
        }

        if (flag == 0)
            printf("%d ", low);

        ++low;
    }

    return 0;
}

OUTPUT:

Enter two numbers(intervals): 20 
50
Prime numbers between 20 and 50 are: 23 29 31 37 41 43 47

C program to check whether a number is palindrome or not

PROGRAM:

#include <stdio.h>
int main()
{
    int n, reversedInteger = 0, remainder, originalInteger;

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

    originalInteger = n;

    
    while( n!=0 )
    {
        remainder = n%10;
        reversedInteger = reversedInteger*10 + remainder;
        n /= 10;
    }

   
    if (originalInteger == reversedInteger)
        printf("%d is a palindrome.", originalInteger);
    else
        printf("%d is not a palindrome.", originalInteger);
    
    return 0;
}

OUTPUT:

Enter an integer: 1001
1001 is a palindrome.

C program to calculate the power of a number

PROGRAM-1:

Power of a number using while loop

#include <stdio.h>
int main()
{
    int base, exponent;

    long long result = 1;

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

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

    while (exponent != 0)
    {
        result *= base;
        --exponent;
    }

    printf("Answer = %lld", result);

    return 0;
}

OUTPUT:

Enter a base number: 3
Enter an exponent: 4
Answer = 81

PROGRAM-2:

Power using pow() function

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

int main()
{
    double base, exponent, result;

    printf("Enter a base number: ");
    scanf("%lf", &base);

    printf("Enter an exponent: ");
    scanf("%lf", &exponent);

    
    result = pow(base, exponent);

    printf("%.1lf^%.1lf = %.2lf", base, exponent, result);

    return 0;
}

OUTPUT:

Enter a base number: 2.3
Enter an exponent: 4.5
2.3^4.5 = 42.44

C program to reverse a number

PROGRAM:

#include <stdio.h>
int main()
{
    int n, reversedNumber = 0, remainder;

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

    while(n != 0)
    {
        remainder = n%10;
        reversedNumber = reversedNumber*10 + remainder;
        n /= 10;
    }

    printf("Reversed Number = %d", reversedNumber);

    return 0;
}

OUTPUT:

Enter an integer: 2345
Reversed Number = 5432

C program to count number of digits in an integer

PROGRAM:

#include <stdio.h>
int main()
{
    long long n;
    int count = 0;

    printf("Enter an integer: ");
    scanf("%lld", &n);

    while(n != 0)
    {
        n /= 10;
        ++count;
    }

    printf("Number of digits: %d", count);
}

OUTPUT:

Enter an integer: 3452
Number of digits: 4