CGFloat result=100/126;
NSLog(@\"%0.5f\",result);
the output of above code is 0.00000 but when i check it on calculator then the value is 0.79365.
May be because your variables are integers. Do this
CGFloat result=100.0/126.0;
NSLog(@"%0.5f",result);
The problem is as both operands of division are integers, integer division is performed and its result is 0. To get proper value you need to make sure that at least one of your operands is floating point number:
CGFloat result=100.0f/126;