/* program entry */

int main (void)

{

int n,/* n stores the number you entered */

s; /* s stores the sum you want to add */

/* First read an integer from the command line and store it in n */

scanf ("%d",&; n);

/* If the read integer is negative, the negative is positive, and it is changed into the corresponding opposite number through the negative sign */

/* If the N is still negative without this step, then the remainder is negative when the remainder is calculated */

/* If the negative number is added to the sum S, the result is naturally incorrect */

If (n < ) n = -n;

/* *

* When n is not equal to , the loop continues

* Because the value of n will be constantly changed in the loop body, it will eventually become */

*/

while (n! = )

{

/* By modulo operation, the remainder of n divided by 1 is obtained, that is, the present single digit of n */

/* If n = 327, then the quotient of n divided by 1 is 32, and the remainder is a digit of 7 */

s = s+n% 1;

/* In C, when the int integer variable is divided by the int integer variable, the decimal part of the result will be directly removed, so the quotient is an integer */

/* 327 divided by 1, and the accurate result is 32.7. After the decimal part is removed, the result is 32 */

/*, and then this quotient is assigned to N as the new value of N, which makes N remove the original value. It becomes a two-digit number */

/* 327/1, and the result is a two-digit number 32 */

n = n/1;

/* Next cycle, take out the single digit of N and add it to the sum S */

/* When N changes from two digits to one digit */

/* Next cycle, because n% 1 is itself */

/* The result of N/1 is , and is the new value of N. = when the judgment is not established, the loop ends */

}

printf ("%d \ n", s);

return ;

}

/* If you don't understand anything, please ask. */