{
int i，thou，hun，ten，data，j；
int ab，CD；
for(I = 0； I & lt200; i++)
{
thou = a[I]/ 1000； //Thousands of digits, because it is an integer, four digits divided by 1000 is thousands of digits. The same below.
hun = a[I]% 1000/ 100； //Hundred digits, where% is first used for the remainder, such as: 6543% 1000+543, and then divided by 100 to get the five hundred digits.
Ten = a [I]%100/10; //Ten digits
data = a[I]% 10； //digital number
If (through = = 0 || data = = 0)//Because both the thousand bits and the unit bits are new ten bits, the assignment of ab and cd below is only performed if it is not required to be 0;
Continue;
Ab = 10 * thou+ ten; //new number ab
CD = 10 * data+hun; //New number cd
if(is prime(ab)& amp； & Isprime (cd))//Call isprime to check whether ab and CD are prime numbers. If so, execute the following statement {0}.
{
b[CNT]= a[I]； //Store the qualified value of a[i] in the array b[].
cnt++； //As an accumulator, it is also the subscript of B array.
}
}//These 200 numbers have been filtered.
for(I = 0； I< CNT-1; I++) //cnt subperiod
for(j = I+ 1； J & LTCTJ++)//CNT-I cycles
if(b[I]& lt； B[j]) // See which is bigger?
{If b[j] is large.
data = b[I]； //
b[I]= b[j]； //
B[j] = data; //three steps, b[i], b[j] exchange
}//After the loop ends, you get an array from big to small.
}