Chapter 6 - Correction of Exercise 7

[microapple]

Code: (Objective-C)

// Program to generate a table of prime numbers

#import <Foundation/Foundation.h>

int main (int argc, char * argv[])
{
    @autoreleasepool
    {
        int p, d, isPrime;
        

        NSLog (@"2"); // two in the only eve number so then we can skeep all eve numbers because they can be divided by 2
        
        // we will not check eve numbers because we know that only two is prime all other ever numbers
        // can be divided by two
        
        for ( p = 3; p <= 50; p+=2 )
        {
            isPrime = 1;
          
            for ( d = 3; d < p; d+=2 )
                
                if ( p % d == 0 )
                {
                    isPrime = 0;
                    // if we dicover that the number can be divided by other number
                    // why conitue ? 
                    break ;
                }
            
                if ( isPrime != 0 )
                NSLog (@"%i ", p);
        }
    }
    return 0;
}

[EthanChu]

 
Break is not use for this kind application.
I think you can change the condition
 
for ( d = 3; d < p; d+=2 )   --> will still run
     if ( p % d == 0 ) 
                { 
                    isPrime = 0; 
 // if we dicover that the number can be divided by other number 
                    // why conitue ?   
                    break ; 
                } 
 
like below
 for ( d = 3; d < p && isPrime == 1; d+=2 )
 program will go next d+=2, after isPrime = 0