This book is now obsolete Please use CSAwesome instead.
3.9. Common Mistakes¶
forgetting that Java is case sensitive -
myScore
is not the same asmyscore
.forgetting to specify the type when declaring a variable (using
name = value;
instead oftype name = value;
)using a variable name, but never declaring the variable.
using the wrong name for the variable. For example calling it
studentTotal
when you declare it, but later calling ittotal
.using the wrong type for a variable. Don’t forget that using integer types in calculations will give an integer result. So either cast one integer value to double or use a double variable if you want the fractional part (the part after the decimal point).
using
==
to compare double values. Remember that double values are often an approximation. You might want to test if the absolute value of the difference between the two values is less than some amount instead.assuming that some value like 0 will be smaller than other
int
values. Remember thatint
values can be negative as well. If you want to set a value to the smallest possibleint
values useInteger.MIN_VALUE