C# programming problem: write a function to calculate the number of prime numbers in the interval of 500-800, and add and subtract intervals to calculate the sum in descending order.

Hello, the procedure is as follows, only playing mobile games.

# include & ltstdio.h & gt

# include & ltmath.h & gt

int main()

{

int i，m，cn=0，sum=0，sign = 1；

for(m = 799； m & gt=500; m-=2)？ //Because even numbers must not be prime numbers?

{

for(I = 2； I< = sqrt (m); i++)

If (m%i==0)

Break;

If (i & gtsqrt(m))

{

cn++；

Sum+= symbol * m；;

sign =-sign；

}

}

printf("%d？ %d？ \n”、cn、sign)； ?

}