# defineteTRUE 1/defines the constant true as1.
#define FALSE 0 // defines the constant FALSE as 0.
Typedef int Bool// defines the synonym Bool for int. This sentence and the above two sentences forged a Boolean type.
Main()// main function
{
bool digit _ seen[ 10]= { 0 }； //Define a Bool (integer) array named digit_seen, and define each array element as 0 (FALSE).
Int number; //Define an int (integer) variable named digit.
long int n； //define a long integer variable named n.
Printf ("Enter a number:"); //Print (output) "Enter a number on the screen" (excluding quotation marks).
scanf("%ld "，& ampn)； //enter a long integer variable and pass it to n.
while(n & gt； 0) {// The loop starts with n >; 0, the loop is executed.
digit = n % 10； //Assign the remainder of n divided by 10 to the digit variable.
If(digit_seen[digit]) // If the digit element of the digit_seen array is not 0 (TRUE)
Break; //and then exit this loop. Combined with the following, if there are two duplicates in n, exit the loop, because n >； at this time; 0, so it provides conditions for the later judgment.
digit _ seen[digit]= TRUE； //If the loop does not exit, the program will run to this sentence. Function: Record that the first digit of the digit_seen array is TRUE, indicating that one digit in n has been used.
n/= 10； //This sentence has the same effect as n=n/ 10, that is, the integer part of n minus 10 times is assigned to n (integer divided by integer or integer).
}//Judge at the beginning of the loop. If n/ 10 is already 0, the loop ends. At this time, n=0 makes conditions for the later judgment.
If (n & gt0) // If n>0, that is, the situation of quitting the loop halfway, it means that there are duplicates in n..
Printf ("Duplicate Numbers \ n \ n"); //output "repeat number" and two line breaks (representing "repeat number")
Else // There is only one possibility of Else here, that is, n=0 means that the loop ends normally, and there is no duplicate number in n..
Printf ("No duplicate numbers \ n \ n"); //Output "No Duplicate Numbers" and two line breaks.
Returns 0; //The program ends normally
}
/* Summary, this program judges whether all digits of a number are repeated, such as 12457 1 repeated, 123456 not repeated */