How do exit two nested loops? [duplicate]
I have been using Java for quite som开发者_运维知识库e time, yet my education in loops is somewhat lacking. I know how to create every loop that exists in java and break out of the loops as well. However, I've recently thought about this:
Say I have two nested loops. Could I break out of both loops using just one
break
statement?
Here is what I have so far.
int points = 0;
int goal = 100;
while (goal <= 100) {
for (int i = 0; i < goal; i++) {
if (points > 50) {
break; // For loop ends, but the while loop does not
}
// I know I could put a 'break' statement here and end
// the while loop, but I want to do it using just
// one 'break' statement.
points += i;
}
}
Is there a way to achieve this?
In Java you can use a label to specify which loop to break/continue:
mainLoop:
while (goal <= 100) {
for (int i = 0; i < goal; i++) {
if (points > 50) {
break mainLoop;
}
points += i;
}
}
Yes, you can write break with label e.g.:
int points = 0;
int goal = 100;
someLabel:
while (goal <= 100) {
for (int i = 0; i < goal; i++) {
if (points > 50) {
break someLabel;
}
points += i;
}
}
// you are going here after break someLabel;
There are many ways to skin this cat. Here's one:
int points = 0;
int goal = 100;
boolean finished = false;
while (goal <= 100 && !finished) {
for (int i = 0; i < goal; i++) {
if (points > 50) {
finished = true;
break;
}
points += i;
}
}
Update: Wow, did not know about breaking with labels. That seems like a better solution.
Elementary, dear Watson ...
int points = 0;
int goal = 100;
while (goal <= 100) {
for (int i = 0; i < goal; i++) {
if (points > 50) {
goal++;
break;
}
points += i;
}
}
or
int points = 0;
int goalim = goal = 100;
while (goal <= goalim) {
for (int i = 0; i < goal; i++) {
if (points > 50) {
goal = goalim + 1;
break;
}
points += i;
}
}
You can reset the loop control variables.
int points = 0;
int goal = 100;
while (goal <= 100) {
for (int i = 0; i < goal; i++) {
if (points > 50) {
i = goal = 101;
}
points += i;
}
}
You shouldn't use labels in objective language. You need to rewrite the for/while condition.
So your code should look like:
int points = 0;
int goal = 100;
while (goal <= 100 && points <= 50) {
for (int i = 0; i < goal && points <= 50; i++) {
points += i;
}
}
// Now 'points' is 55
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