Invalid memory reference (SIGSEGV) and incomplete implementation of class error - objective-c

Question

I am writing a small recursive function to calculate the sum of integers from an array. However, I am getting errors and warnings. Anybody help me to solve these issues?
#import <Foundation/Foundation.h>
#interface SumIntegers:NSObject
{
NSInteger result;
}
-(NSInteger)calcutateSum:(NSInteger)value;
-(void) printSum;
#end
#implementation SumIntegers
-(NSInteger)calculateSum:(NSInteger)value
{
NSInteger sum = 0;
//sum = sum + [[self calculateSum:[array objectAtIndex:i]] integerValue];
sum = sum + [self calculateSum:value];
result = sum;
return result;
}
-(void) printSum
{
NSLog(#"Sum of integer list is %i",result);
}
#end
int main (int argc, const char * argv[])
{
NSInteger i;
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSMutableArray *intArray = [NSMutableArray arrayWithObjects:[NSNumber numberWithInteger:1],[NSNumber numberWithInt:3],[NSNumber numberWithInt:5]
,[NSNumber numberWithInt:7],[NSNumber numberWithInt:9],nil];
SumIntegers *sumIntegers = [[SumIntegers alloc]init];
for (i = 0; i<[intArray count]; i++)
{
NSInteger hhh = [sumIntegers calculateSum:[[intArray objectAtIndex:i] integerValue]];
}
[sumIntegers printSum];
[pool drain];
return 0;
}
What I did is I created an interface SumIntegers and created a recursive function to calculate the sum of integers. However, somehow this function is not recognized and also getting warning "incomplete implementation of class #end" and memory error.
Warning(s):
source_file.m:31:1: warning: incomplete implementation of class ‘SumIntegers’
#end
^
source_file.m:31:1: warning: method definition for ‘-calcutateSum:’ not found
source_file.m: In function ‘main’:
source_file.m:44:19: warning: unused variable ‘hhh’ [-Wunused-variable]
NSInteger hhh = [sumIntegers calculateSum:[[intArray objectAtIndex:i] integerValue]];
^
Error(s):
Invalid memory reference (SIGSEGV)

Answer 1

Here is my answer to above problem. There is no need of return value or argument in the calculateSum method. Simply adding array value into the sum and then calling the calculateSum method again until num is less than array count.
#import <Foundation/Foundation.h>
#interface SumOfIntegers:NSObject
{
NSMutableArray *intArray;
NSInteger sum;
NSInteger num;
}
#property NSMutableArray *intArray;
#property NSInteger sum, num;
-(void) calculateSum;
#end
#implementation SumOfIntegers
#synthesize intArray, sum, num;
-(void) calculateSum{
if(num < [intArray count])
{
NSLog(#"number is.... %i", num);
sum = sum + [[intArray objectAtIndex:num++] integerValue];
[self calculateSum];
}
else
{
NSLog(#"Sum of integers is %i", sum);
}
}
#end
int main (int argc, const char *argv[])
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSMutableArray *array = [NSMutableArray arrayWithObjects:[NSNumber numberWithInteger:1],[NSNumber numberWithInt:3],[NSNumber numberWithInt:5]
,[NSNumber numberWithInt:7],[NSNumber numberWithInt:9],nil];
SumOfIntegers *sumOfIntegers = [[SumOfIntegers alloc]init];
sumOfIntegers.intArray = array;
sumOfIntegers.sum = 0;
sumOfIntegers.num = 0;
[sumOfIntegers calculateSum];
[pool drain];
return 0;
}

Answer 2

In modern ObjC:
int main(int argc, const char * argv[]) {
#autoreleasepool {
NSArray *nums = #[#(1), #(2), #(3)];
NSLog(#"%#", [nums valueForKeyPath:#"#sum.self"]);
}
return 0;
}