I need help regarding C program to reverse a number

Question

#include <stdio.h>
int main()
{
long num, reverse = 0, temp, remainder;
printf("Enter the number\n");
scanf("%ld", &num);
temp = num;
while (num > 0)
{
remainder = num % 10;
reverse = reverse * 10 + remainder;
num /= 10;
}
printf("Given number = %ld\n", temp);
printf("Its reverse is = %ld\n", reverse);
}
Please explain to me in simple language and how reverse of an integer comes as output
and how this program works

Answer 1

Samadhan Patil let me try to explain it for input as 123...
1.123 > 0 and while condition is true... remainder is 3 and reverse is 0*10+3 = 3 and num i.e. 123 becomes 12
2. 12 > 0 and again while condition is true... remainder is 2 and reverse is 3*10 + 2 = 32 and num i.e. 12 becomes 1
3. 1> 0 and again while condition is true... remainder is 1 and reverse is 32*10 + 1 = 321 and num i.e. 1 becomes 0
this ends while loop and reverse which is output is 321

Answer 2

How to make a program for
print every way of writing n as a sum of natural numbers, with repetitions, in non decreasing order. If we input 5 then its output 1+1+1+1+1 , 1+1+1+2 , 1+1+3 , 1+2+2 , 1+4, 2+3 , 5