float x = 0.1;
if (x==0.1) {
// do something
}
This won't work, because a float is what it is.. a number that "floats". A 0.1 is not precisely a 0.1. In the case of above, x being set to 0.1, but it may hold a value of 0.1000000001 or -0.100000002341 and so on.
So the correct way to compare a float is to set a range.
float x = 0.1;
if ((x<=0.10005)&&(x>=0.00005)) {
// do something
}
There is another variable comparison mistakes that people often do, and asked why it does not work and that is comparing NSString.
NSString *myStr = @"My House";
if (result==myStr) {
// do something
}
This, too, will not work because an NSString is a pointer. A pointer is like an address to your home. Your house needs a renovation, but you are trying to renovate the address. Which is absurd.
There are often a simple function to compare string objects, an in XCode, it is called isEqualToString:
Thus, the correct way to do it is:
NSString *myStr = @"My House";
if ([result isEqualToString:myStr]) {
// do something
}
You can interchange result and myStr in that syntax, no problem. I hope this simple tutorial post helps noobies to understand the variables and how to compare them the correct way. As this tutorial is a simple one, there are no downloadable source codes.
