C language essence-identify prime numbers, essence identify prime numbers

C language essence-identify prime numbers, essence identify prime numbers
# Include <math. h>
# Include <stdio. h>
Int IsPrimeNumber (int number );
Int main ()
{
Int n, ret;
Printf ("Input n :");
Scanf ("% d", & n );
Ret = IsPrimeNumber (n );
 
If (ret! = 0) // 01
{
Printf ("% d is a prime number \ n", n );
}
Else
{
Printf ("% d is not a prime number \ n", n );
}
 
Return 0;
}
 
// Function: determines whether the number is a prime number. The function returns a non-zero value, indicating that the number is a prime number. Otherwise, the number is not a prime number.
Int IsPrimeNumber (int number)
{
Int I;

If (number <= 1) return 0; // negative number, 0, and 1 are not prime numbers
For (I = 2; I <= sqrt (number); I ++)
{
If (number & I = 0) // divisible, not a prime number
Return 0;
}
 
Return 1;
}