Dart – Loops
A looping statement in Dart or any other programming language is used to repeat a particular set of commands until certain conditions are not completed. There are different ways to do so. They are:
- for loop
- for… in loop
- for each loop
- while loop
- do-while loop
for loop
For loop in Dart is similar to that in Java and also the flow of execution is the same as that in Java.
Syntax:
for(initialization; condition; text expression){
// Body of the loop
}
Control flow:
Control flow goes as:
- initialization
- Condition
- Body of loop
- Test expression
The first is executed only once i.e in the beginning while the other three are executed until the condition turns out to be false.
Example:
Dart
// Printing w3wiki 5 timesvoid main(){ for (int i = 0; i < 5; i++) { print('w3wiki'); }} |
Output:
w3wiki w3wiki w3wiki w3wiki w3wiki
for…in loop
For…in loop in Dart takes an expression or object as an iterator. It is similar to that in Java and its execution flow is also the same as that in Java.
Syntax:
for (var in expression) {
// Body of loop
}
Example:
Dart
void main(){ var w3wiki = [ 1, 2, 3, 4, 5 ]; for (int i in w3wiki) { print(i); }} |
Output:
1 2 3 4 5
for each … loop
The for-each loop iterates over all elements in some container/collectible and passes the elements to some specific function.
Syntax:
collection.foreach(void f(value))
Parameters:
- f( value): It is used to make a call to the f function for each element in the collection.
Dart
void main() { var w3wiki = [1,2,3,4,5]; w3wiki.forEach((var num)=> print(num)); } |
Output:
1 2 3 4 5
while loop
The body of the loop will run until and unless the condition is true.
Syntax:
while(condition){
text expression;
// Body of loop
}
Example:
Dart
void main(){ var w3wiki = 4; int i = 1; while (i <= w3wiki) { print('Hello Geek'); i++; }} |
Output:
Hello Geek Hello Geek Hello Geek Hello Geek
do..while loop
The body of the loop will be executed first and then the condition is tested.
Syntax:
do{
text expression;
// Body of loop
}while(condition);
Example:
Dart
void main(){ var w3wiki = 4; int i = 1; do { print('Hello Geek'); i++; } while (i <= w3wiki);} |
Output:
Hello Geek Hello Geek Hello Geek Hello Geek
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