Xcode中的未知错误

Question

I am following the instructions for a tutorial but I cannot figure out what is wrong. I have double checked everything. I put the the compiler errors in the code's comments below. Sorry, this will probably show how much of a noob I am.

//  main.m


#import <Foundation/Foundation.h>
#import "LotteryEntry.h"

int main (int argc, const char * argv[])
{

    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

   // Creates the date object

    NSCalendarDate *now = [[NSCalendarDate alloc]init];

    //Seed the random number generator

    srandom(time(NULL));
    NSMutableArray * array;
    array = [[NSMutableArray alloc]init];

    int i;
    for (i = 0; i < 10; i++) {

        //create a date/time object that is 'i' weeks from now

        NSCalendarDate *iWeeksFromNow;
        iWeeksFromNow = [now dateByAddingYears:0
                                         months:0
                                           days:(i * 7)
                                          hours:0
                                        minutes:0
                                         second:0];
    }

     //create the LotteryEntry object

     LotteryEntry *newEntry = [[LotteryEntry alloc]init];
     [newEntry prepareRandomNumbers];
     [newEntry setEntryDate: iWeeksFromNow]; 

//Error says "Use of undeclared identifier "iWeeksFromNow'. Did I not declare it above?

     //add the lottery entry object to the array

     [array addObject:newEntry];

     }

     for (LotteryEntry *entryToPrint in array) { 

//Error says " Expected identifier or '('


         //Display it's contents

         NSLog(@"%@", entryToPrint);

     }





[pool drain];
return 0;       
//Error says " Expected identifier or '('
}                  
//Error says " Expected External declaration

Answer 1

你在for循环中声明iWeeksFromNow，这就是为什么编译器不认为它存在于外部声明它，并在里面为它赋值

Answer 2

当你调用-dateByAddingYears方法时，你有一个额外的结束} 。

Answer 3

First error : you declare iWeeksFromNew inside a for loop, thus it's unreachable from outside. You have to declare before the beginning of the loop.

Second error : you have a bracket '}' after [array addObject:newEntry]; so the compiler thinks its the end of your method, remove it.

That should fix all other error you have

Answer 4

First, iWeeksFromNow is declared within the scope of a for loop, so it will be visible only within that loop. Second, as pointed out by Black Frog , you have an extra closing parenthesis.

Answer 5

Move the declaration out that loop block. You've got a scope problem here: The iWeeksFromNew only exists within the loop

NSCalendarDate *iWeeksFromNow;
int i;
for (i = 0; i < 10; i++) {

    //create a date/time object that is 'i' weeks from now
    iWeeksFromNow = [now dateByAddingYears:0
                                     months:0
                                       days:(i * 7)
                                      hours:0
                                    minutes:0
                                     second:0];
}