Punataro Puhn Chaturaphit - 9 months ago 53

Objective-C Question

I would like to know how to evaluate a string representation of an equation as if it were a real equation:

`if(@"15+14==23")`

{

//True statement...

}

else

{

//False statement....

}

I want to return "false" because 15+14 does not equal 23. How can I get this to work?

Answer

Here is an example how to do it with `NSPredicate`

:

```
NSPredicate *p = [NSPredicate predicateWithFormat:@"1+2==3"];
NSLog(@"%d", [p evaluateWithObject:nil]);
p = [NSPredicate predicateWithFormat:@"1+2==4"];
NSLog(@"%d", [p evaluateWithObject:nil]);
```

The first `NSLog`

produces `1`

because `1+2==3`

is true; the second produces `0`

.