Common Mistakes

Year 11 Computer Science – Java Variables Common Mistakes

forgetting that Java is case-sensitive – myScore is not the same as myscore.
forgetting to specify the type when declaring a variable (using name = value; instead of type 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 it total.
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 test for equality instead of ==
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.