Are there any ways shorter to write the condition of if/else statement which compares 3 values than "If ( value1 == value2 && value2 == value3) {... " ?
Practice it counts "if (value1 == value2 == value3) {..." as error
No because == is a relational operator that can only compare two operands. The code that you tried would compare the first two and find it to be true or false and then compare true/false to value3 which results in the error.
I don't think there is another way of comparing 3 values other than using && or || statements, in this example.