I hope this isn't a stupid question but I have looked up every example I can find and it still seems like I have this code right and it still isn't working... I enter one number and it moves on to the next line of code instead of looping. I'm using this to fill an array with user input numbers. I appreciate any help, thanks.
for(i=0; i<9; i++);
{
System.out.println ("Please enter a number:");
Num[i] = keyboard.nextDouble();
Sum += Num[i];
Product *= Num[i];
}
The ; at the end of the for loop is taken as an empty statement, the equivalent of an empty block for your for-loop. The compiler is reading your code as:
int i;
....
for(i=0; i<9; i++)
/* no-op */;
/* inline block with no relation to for-loop */
{
System.out.println ("Please enter a number:");
Num[i] = keyboard.nextDouble();
Sum += Num[i];
Product *= Num[i];
}
Remove the ; to get your intended behavior.
If you don't need the i outside of the loop, you could move its declaration within the for statement.
for(int i=0; i<9; i++)
{
// `i` is only usable here now
}
// `i` is now out of scope and not usable
Using this syntax when the erroneous semicolon ; was present would have produced a compile error that would alerted you to the erroneous ; earlier. THe compiler would see this:
for(int i=0; i<9; i++)
/* no-op */;
/* inline block with no relation to for-loop */
{
System.out.println ("Please enter a number:");
Num[i] = keyboard.nextDouble(); // compile error now - `i` is out-of-scope
Sum += Num[i];
Product *= Num[i];
}
This would be an example why it is good practice to limit the scope of variables when possible.
Noticed the ';' at the end of for(i=0; i<9; i++); ? ^_^
remove the last character semicolon from for loop line ............
To avoid this mistake in future you should always use a fresh variable in a for loop. Instead of:
for (i = 0; ...
write
for (int i = 0; ...
That way it would be a compile-time error, since the variable i would not be in scope in the following block.
for (int i = 0; i < 5; i++); { i++; } the identifier i goes out of scope after the semicolon and before the block.
There shouldn't be a semicolon at the end of the first line. It indicates your loop is empty.
The answer has already been given, but I'd like to add that if you are using an IDE*, there will probably be a warning for those kinds of empty statements and other easy to make, easy to overlook type of mistakes (assinging instead of comparing in conditions for example).
just to let you know. something like this:
for(;;)
;
should send your program into busy-waiting. happened to me in the early days. :)
Just remove that semi-colon after the "for(....)"
for(i=0; i<9; i++); //<---------- over here
you don't have to put a semi-colon over here. Most probably you were aware of that, it happens. Additional points: The syntax for "for" is:
for(initializer; condition; change){
//code here
}
The syntax for "while" is:
while(condition without semi-colon){
//code here
}
The syntax for "do-while" is:
do{
//code here
}while(condition);//<---------------semi-colon here.
Most probably you were confused between "for" and "do-while" loops, that happens. I too, when I was a beginner, used to be confused of such things.
iis not declared. Unless you haveideclared globally somewhere at the top.Num,keyboard,Sum, orProduct.