CODEWITHSUNDEEP
javaloops
Peter Hwang
Peter Hwang

Reputation: 991

statements in a for loop

I am writing a small program which uses a for loop. 

1 Scanner sc = new Scanner(System.in);
2 int T = sc.nextInt();
3 for(int j = 1; j < 2T-1; j+=2){
4     doSomething();
5 }

However, this one gives me an error.
The error message says:

javac Main.java -g
Main.java:12: error: ';' expected
            for(int j = 1; j < 2T-1; j+=2){
                                ^
Main.java:12: error: not a statement
            for(int j = 1; j < 2T-1; j+=2){
                                 ^
Main.java:12: error: ')' expected
            for(int j = 1; j < 2T-1; j+=2){
                                   ^
Main.java:12: error: ';' expected
            for(int j = 1; j < 2T-1; j+=2){
                                         ^
4 errors

I don't quite understand the 'statement' in an error message.

1) How come it produces errors?
2) What's the difference between statement and expression?

Upvotes: 0

Views: 36

Answers (2)

Elliott Frisch
Elliott Frisch

Reputation: 201447

Java isn't an algebraic math system. This

for(int j = 1; j < 2T-1; j+=2){

should be

for(int j = 1; j < (2*T) - 1; j += 2){

2T-1 simply isn't a valid statement; variable names cannot start with a number, the compiler detects that 2 would be a valid statement and is communicating that. However, T-1 is then in an unexpected place.

Upvotes: 1

Lasitha Yapa
Lasitha Yapa

Reputation: 4609

You have to use 

for(int j = 1; j < (2*T)-1; j+=2){

or

for(int j = 1; j < 2*T-1; j+=2){

Both will give you the same result.

Upvotes: 0

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