Java Reference
In-Depth Information
Note
Be aware that a nested loop may take a long time to run. Consider the following loop
nested in three levels:
for
(
int
i =
0
; i <
10000
; i++)
for
(
int
j =
0
; j <
10000
; j++)
for
(
int
k =
0
;k <
10000
; k++)
Perform an action
The action is performed one trillion times. If it takes 1 microsecond to perform the action,
the total time to run the loop would be more than 277 hours. Note that 1 microsecond is
one millionth (10
-6
) of a second.
4.19
✓
✓
How many times is the
println
statement executed?
Check
Point
for
(
int
i =
0
;i <
10
; i++)
for
(
int
j =
0
; j < i; j++)
System.out.println(i * j)
4.20
Show the output of the following programs. (
Hint
: Draw a table and list the variables
in the columns to trace these programs.)
public class
Test {
/** Main method */
public static void
main(String[] args) {
for
(
int
i =
1
; i <
5
; i++) {
int
j =
0
;
while
(j < i) {
System.out.print(j +
" "
);
j++;
public class
Test {
/** Main method */
public static
void main(String[] args) {
int
i =
0
;
while
(i <
5
) {
for
(
int
j = i; j >
1
;j——)
System.out.print(j +
" "
);
System.out.println(
"****"
);
i++;
}
}
}
}
}
}
}
(a)
(b)
public class
Test {
public static void
main(String[] args) {
int
i =
5
;
while
(i >=
1
) {
int
num =
1
;
for
(
int
j =
1
; j <= i; j++) {
System.out.print(num +
"xxx"
);
num *=
2
;
public class
Test {
public static void
main(String[] args) {
int
i =
1
;
do
{
int
num =
1
;
for
(
int
j =
1
; j <= i; j++) {
System.out.print(num +
"G"
);
num +=
2
;
}
}
System.out.println();
i——;
System.out.println();
i++;
}
while
(i <=
5
);
}
}
}
}
}
(c)
(d)
