Conditions in Dart
Conditions In Dart
When you write a computer program, you need to be able to tell the computer what to do in different situations. With conditions, you can control the flow of the dart program. Suppose you need to execute a specific code when a particular situation is true. In that case, you can use conditions in Dart. E.g., a calculator app must perform subtraction if the user presses the subtract button and addition if the user taps the add button.
Types Of Condition
You can use following conditions to control the flow of your program.
- If Condition
- If-Else Condition
- If-Else-If Condition
- Switch case
If Condition
The easy and most common way of controlling the flow of a program is through the use of an if statement. If statement allow us to execute a code block when the given condition is true. Conditions evaluate boolean values.
Syntax
if(condition) {
Statement 1;
Statement 2;
.
.
Statement n;
}
Example Of If Condition
It prints whether the person is a voter. If the person’s age is greater and equal to 18, it will print, You are a voter.
void main()
{
var age = 20;
if(age >= 18){
print("You are voter.");
}
}
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If-Else Condition
If the result of the condition is true, then the body of the if-condition is executed. Otherwise, the body of the else-condition is executed.
Syntax
if(condition){
statements;
}else{
statements;
}
Example Of If-Else Condition
Dart program prints whether the person is a voter or not based on age.
void main()
{
int age = 12;
if(age >= 18){
print("You are voter.");
}else{
print("You are not voter.");
}
}
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Condition Based On Boolean Value
If the married status is false, it prints you are single; otherwise, it will print you are married.
void main()
{
bool isMarried = false;
if(isMarried){
print("You are married.");
}else{
print("You are single.");
}
}
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If-Else-If Condition
When you have multiple if conditions, then you can use if-else-if. You can learn more in the example below. When you have more than two conditions, you can use if, else if, else in dart.
Syntax
if(condition1){
statements1;
}else if(condition2){
statements2;
}else if(condition3){
statements3;
}
.
.
.
else(conditionN){
statementsN;
}
Example Of If-Else-If Condition
This program prints the month name based on the numeric value of that month. You will get a different result if you change the number of month.
void main() {
int noOfMonth = 5;
// Check the no of month
if (noOfMonth == 1) {
print("The month is jan");
} else if (noOfMonth == 2) {
print("The month is feb");
} else if (noOfMonth == 3) {
print("The month is march");
} else if (noOfMonth == 4) {
print("The month is april");
} else if (noOfMonth == 5) {
print("The month is may");
} else if (noOfMonth == 6) {
print("The month is june");
} else if (noOfMonth == 7) {
print("The month is july");
} else if (noOfMonth == 8) {
print("The month is aug");
} else if (noOfMonth == 9) {
print("The month is sep");
} else if (noOfMonth == 10) {
print("The month is oct");
} else if (noOfMonth == 11) {
print("The month is nov");
} else if (noOfMonth == 12) {
print("The month is dec");
} else {
print("Invalid option given.");
}
}
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Find Greatest Number Among 3 Numbers
Dart program, which finds the greatest number among three numbers.
void main()
{
int num1 = 1200;
int num2 = 1000;
int num3 = 150;
if(num1 > num2 && num1 > num3){
print("Num 1 is greater: i.e $num1");
}
if(num2 > num1 && num2 > num3){
print("Num2 is greater: i.e $num2");
}
if(num3 > num1 && num3 > num2){
print("Num3 is greater: i.e $num3");
}
}
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Video
Watch our video on the conditions in Dart.