#include<stdio.h>

void CheckArmstrongNumber(int num){
    int temp = num;
    int totalDigits = 0;
    int sum = 0;

    if (temp == 0){
        totalDigits = 1;
    }else{
        while (temp != 0){
            totalDigits++;
            temp = temp / 10;
        }
    }

    temp = num;

    while (temp != 0){
        int digit = temp % 10;
        int powerResult = 1;
        int i;

        for (i = 1; i <= totalDigits; i++){
            powerResult = powerResult * digit;
        }

        sum = sum + powerResult;
        temp = temp / 10;
    }

    if (sum == num){
        printf("%d is an Armstrong number.\n", num);
    }else{
        printf("%d is not an Armstrong number.\n", num);
    }
}

char checkGrade(float score){
    int gradeValue;
    if (score < 0 || score > 100){
        return 'X';
    }
    gradeValue = (int)score / 10;

    switch (gradeValue){
        case 10:
        case 9:
        case 8:
            return 'A';

        case 7:
            return 'B';

        case 6:
            return 'C';

        case 5:
            return 'D';

        default:
            return 'F';
    }
}

int checkPrimeNumbers(int num){
    int i;
    if (num < 2){
        return 0;
    }
    for (i = 2; i * i <= num; i++){
        if (num % i == 0){
            return 0;
        }
    }
    return 1;
}

void checkPalindrome(int num){
    int temp = num;
    int reversedNum = 0;

    while (num != 0){
        int digit = num % 10;
        reversedNum = reversedNum * 10 + digit;
        num = num / 10;
    }

    if (temp == reversedNum){
        printf("%d is a palindrome number.\n", temp);
    }else{
        printf("%d is not a palindrome number.\n", temp);
    }
}

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

    printf("Enter your score = ");
    float score;
    scanf("%f",&score);
    printf("Your grade is %c\n",checkGrade(score));

    printf("Enter a number to check if it is prime or not : ");
    int num;
    scanf("%d",&num);
    if(checkPrimeNumbers(num)==1){
        printf("It is a prime number\n");
    }else{
        printf("It is not a prime number\n");
    }

    printf("Enter a number to check palindrome: ");
    scanf("%d", &num);
    checkPalindrome(num);
}