Loops in Dart

Looping

In Programming, looping is used to execute the block of code repeatedly for a specified number of times or until it meets a specified condition. For E.g, For printing name 10 times, you can use loop.

Types of Loop

For Loop
For each Loop
While Loop
Do While Loop

For Loop

This is the most common type of loop. You can use for loop to run a block of code multiple times according to condition.

Syntax

for(initialization; condition; increment/decrement){
            statements;
}

Initialization is executed (one time) before the execution of the code block.
Condition defines the condition for executing the code block.
Increment/Decrement is executed (every time) after the code block has been executed.

Example To Print 1 To 10 Using For Loop Increment

void main() {
  for (int i = 1; i <= 10; i++) {
    print(i);
  }
}

Show Output

Example To Print 10 To 1 Using For Loop Decrement

void main() {
  for (int i = 10; i >= 1; i--) {
    print(i);
  }
}

Show Output

For each Loop

The for each loop iterates over all elements of list or variable. It is a higher order function.

Example For List

void main(){
  List<String> footballplayer=['Ronaldo','Messi','Neymar','Hazard'];
  footballplayer.forEach( (names)=>print(names));
}

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Example For Variable

void main(){
   var name=['ram','hari','aastha','kiran'];
   name.forEach((var names)=>print(names));
 }

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While Loop

The body of the loop will run until and unless the condition is true. You must write condition first before statements.

Syntax

while(condition){  
       //statement(s);  
      // Increment (++) or Decrement (--) Operation;  
}

Example To Print 1 To 10 Using While Loop Increment

void main() {
  int i = 1;
  while (i <= 10) {
    print(i);
    i++;
  }
}

Show Output

Example To Print 10 To 1 Using While Loop Decrement

void main() {
  int i = 10;
  while (i >= 1) {
    print(i);
    i--;
  }
}

Show Output

Do While Loop

Do while loop is used to run a block of code multiple times. Simply you can say, the body of the loop will be executed first and then the condition is tested.

Syntax

do{
    statement1;
    statement2;
    .
    .
    .
    statementN;
}while(condition);

Example To Print 1 To 10 Using Do While Loop Increment

void main() {
  int i = 1;
  do {
    print(i);
    i++;
  } while (i <= 10);
}

Show Output

Example To Print 10 To 1 Using Do While Loop Decrement

void main() {
  int i = 10;
  do {
    print(i);
    i--;
  } while (i >= 1);
}

Show Output