Oct 16, 2022by @kodeazy

Error RangeError (index) Index out of range index should be less than 4 4

Home » flutter » Error RangeError (index) Index out of range index should be less than 4 4

flutterdart

import 'package:flutter/material.dart';
void main() {
  String stringToReverse = "accaqqq";
  String reversedString = "";
   for (int j = stringToReverse.length; j >= 0; j--) {//stringToReverse.length gives 7 as j value but total length of stringToReverse variable is 6 so we got RangeError
    reversedString += stringToReverse[j];                
  }
  print(reversedString);
}

In the above code stringToreverse variable length is 6.
stringToReverse.length gives length as 7.

As the stringToReverse.length length is greater than the string lenght we got below error. Output:

Error: RangeError (index): Index out of range: index should be less than 7: 7
at Object.throw_ [as throw] (http://localhost:61643/dart_sdk.js:5041:11)
at String.[dartx._get] ....

By modifying stringToReverse.length to stringToReverse.length-1 we make sure that getting index with in the string range.

import 'package:flutter/material.dart';
void main() {
String stringToReverse = "accaqqq";
String reversedString = "";
for (int j = stringToReverse.length-1; j >= 0; j--) {
reversedString += stringToReverse[j];
}
print(reversedString);
}

Output:

qqqacca