What makes a valid program statement? Exercise 6.6

[stuartjj]

I'm plugging away at exercise 6.6 and can't figure out what's wrong with the program statement (see below in context):

Code: (Objective-C)

for (resultedDivisor; resultedDivisor>=1; resultedDivisor/=10)
            resultedDigit=userEnteredNumber%resultedDivisor;       

I get the xCode error message: Expression result unused.  This error message refers to the variable "resultedDivisor".

Anybody know why I get this error message?  I guess in general I don't understand what makes a valid program statement. 

Code: (Objective-C)

int userEnteredNumber, divisor, resultedDivisor, resultedDigit;
        
NSLog (@"Enter your number.");
scanf ("%i", &userEnteredNumber);
        
        
        for (divisor=1; userEnteredNumber >= divisor; divisor*=10)
            resultedDivisor=divisor;   //produces 10^x where x = number of digits in userEnteredNumber
        
        NSLog(@"Resulted divsor = %i", resultedDivisor);
        
        for (resultedDivisor; resultedDivisor>=1; resultedDivisor/=10)
            resultedDigit=userEnteredNumber%resultedDivisor;                
        
        
    }
    return 0;
}

[stuartjj]

I solved part of this problem.  The issue was with the initial expression of the for statement, which read:

Code: (Objective-C)

for (resultedDivisor; resultedDivisor>=1; resultedDivisor/=10)  
            resultedDigit=userEnteredNumber%resultedDivisor;         

You have to have an assignment here, rather than just a variable.

[john67]

yeah, you've got it, more specifically its with this bit code....

Code: (Objective-C)

resultedDivisor/=10;

which is shorthand for

Code: (Objective-C)

resultedDivisor = resultedDivisor / 10;

this is an assignment

I think you should but the second code snippet actually in the loop

Code: (Objective-C)

for (resultedDivisor; resultedDivisor>=1;)
{
            resultedDivisor/=10;
            resultedDigit=userEnteredNumber%resultedDivisor;
}