Converting String to int

Part of the Fundamentals section of Coddy's Dart journey — lesson 83 of 94.

The int.parse() method converts a string representation of a number into an integer value.

Create a string containing a number:

String numberAsString = '42';

Convert the string to an integer using int.parse():

int number = int.parse(numberAsString);
print(number);

After executing the above code, the output will be:

You can use the converted integer in calculations:

String priceAsString = '100';
int price = int.parse(priceAsString);
int discount = 20;
int finalPrice = price - discount;
print('Final price: $finalPrice');

After executing the above code, the output will be:

Final price: 80

Challenge

Beginner

In this challenge, you'll practice converting a string to an integer using int.parse().

The code contains a string variable ageText that holds a numeric value as text. Your task is to convert this string to an integer using int.parse() and store it in the ageNumber variable.

After converting, the program will add 5 to the age and display the result.

Expected output:

Original age (string): 25
Converted age (integer): 25
Age after adding 5: 30

Cheat sheet

The int.parse() method converts a string representation of a number into an integer value.

String numberAsString = '42';
int number = int.parse(numberAsString);
print(number); // Output: 42

You can use the converted integer in calculations:

String priceAsString = '100';
int price = int.parse(priceAsString);
int discount = 20;
int finalPrice = price - discount;
print('Final price: $finalPrice'); // Output: Final price: 80

Try it yourself

void main() {
  // This string contains a numeric value
  String ageText = "25";
  
  // TODO: Convert ageText to an integer using int.parse()
  // and store the result in the ageNumber variable
  int ageNumber;
  
  // This will add 5 to the age
  int newAge = ageNumber + 5;
  
  // Display the results
  print("Original age (string): $ageText");
  print("Converted age (integer): $ageNumber");
  print("Age after adding 5: $newAge");
}