Definition (Armstrong Number): An n-digit number equal to the sum of the nth powers of its digits. Example: 153 = 13 + 53 + 33 1634 = 14 + 64 + 34 + 44 #include<stdio.h> #include<math.h> int main(){ long int num =153, count = 0, i, temp1, temp2, temp3 = 0; clrscr(); printf(“Enter the number: “); scanf(“%ld”,&num); if(num <= 0){ printf(“\nEnter the number greater than 0”); return 0; } temp1 = temp2 = num; while(temp1!=0){ temp1=temp1/10; count++; } for(i=0;i < count; i++) { temp3 = temp3 + pow((temp2%10),count); temp2 = temp2/10; } if(num == temp3) { printf(“\n %d is an...

#include #include void main(){ char *str; int count = 0,i; clrscr(); printf(“\nEnter the String: “); gets(str); for(i=0;str[i]!=’\0′;i++){ count++; } printf(“\nThe length of the string is %d.”,count); getch(); } Output: Enter the String: Learn C Online The length of the string is 14.

Below is the C program to reverse a given number. This C program will accept a number (in a variable named “num”) and performs an operation to reverse the number. #include <stdio.h> #include <stdlib.h> int main(void) { int num=1234, newNum=0; while(num!=0){ newNum=newNum*10 + num%10; num=num/10; } printf(“\n”); printf(“%d”, newNum); return 1; } Output: 4321 Explanation: The statement while(num!=0) will be executed till value of num !=0 num%10 (read as num mod 10) will return the last digit. So in 1st iteration, it will return 4. So, newNum will become–> 0*10 + 4 –>4 Next line i.e. num/10 will return 123...