CODEWITHSUNDEEP
objective-cnsrange
user1705636
user1705636

Reputation: 233

objectivec - nsrange calculation is strange

It is strange. I expected that the last NSLog print 3 but it wasn't

NSString *value = @"0(234)6";

NSRange beginParenthesis = [value rangeOfString:@"("];
NSRange endParenthesis = [value rangeOfString:@")"];

if (beginParenthesis.location != NSNotFound && endParenthesis.location != NSNotFound)
{
    NSLog(@"%ld", endParenthesis.location); // 5
    NSLog(@"%ld", beginParenthesis.location + 1); // 2
    NSLog(@"%ld", endParenthesis.location - beginParenthesis.location + 1); // 5?
}

And I saved beginParenthesis.location + 1 to variable...it worked well I expected...why?

NSRange beginParenthesis = [value rangeOfString:@"("];
NSRange endParenthesis = [value rangeOfString:@")"];

if (beginParenthesis.location != NSNotFound && endParenthesis.location != NSNotFound)
{
    NSInteger start = beginParenthesis.location + 1;
    NSLog(@"%ld", endParenthesis.location); //5
    NSLog(@"%ld", start); // 2
    NSLog(@"%ld", endParenthesis.location - start); // 3
}

What differece between theses?

Upvotes: 0

Views: 205

Answers (2)

nithinbhaktha
nithinbhaktha

Reputation: 723

Its called Operator precedence. See here.

Upvotes: 1

Neelam Verma
Neelam Verma

Reputation: 3274

Maths Problem:

endParenthesis.location - beginParenthesis.location + 1 gives u ( 5 - 1 + 1) i.e equal to5 . But endParenthesis.location - start gives u 5 - 2 i.e 3.

So you put the parenthesis like this:

 NSLog(@"%ld", endParenthesis.location - (beginParenthesis.location + 1));

Upvotes: 2

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