JavaScript: Create a new string from a given string changing the position of first and last characters
JavaScript Basic: Exercise-23 with Solution
Write a JavaScript program to create a new string from a given string by changing the position of the first and last characters. The string length must be broader than or equal to 1.
This JavaScript program creates a new string from a given string by swapping the positions of the first and last characters. It ensures that the length of the string is greater than or equal to 1 to perform the swap operation safely. By using string manipulation methods like charAt() and concatenation, it constructs the new string with the first and last characters swapped.
Visual Presentation:
Sample Solution:
JavaScript Code:
// Define a function named first_last that takes a parameter str1
function first_last(str1) {
// Check if the length of str1 is less than or equal to 1
if (str1.length <= 1) {
// If true, return str1 as is
return str1;
}
// Extract the substring from the second character to the second-to-last character of str1
mid_char = str1.substring(1, str1.length - 1);
// Return the last character of str1 followed by mid_char and then the first character of str1
return (str1.charAt(str1.length - 1)) + mid_char + str1.charAt(0);
}
// Log the result of calling the first_last function with the argument 'a' to the console
console.log(first_last('a'));
// Log the result of calling the first_last function with the argument 'ab' to the console
console.log(first_last('ab'));
// Log the result of calling the first_last function with the argument 'abc' to the console
console.log(first_last('abc'));
Output:
a ba cba
Live Demo:
See the Pen JavaScript: position of first and last characters.: basic-ex-23 by w3resource (@w3resource) on CodePen.
Flowchart:
ES6 Version:
// Using ES6 arrow function syntax to define the first_last function
const first_last = (str1) => {
// Check if the length of str1 is less than or equal to 1
if (str1.length <= 1) {
// If true, return str1 as is
return str1;
}
// Extract the substring from the second character to the second-to-last character of str1
const mid_char = str1.substring(1, str1.length - 1);
// Return the last character of str1 followed by mid_char and then the first character of str1
return (str1.charAt(str1.length - 1)) + mid_char + str1.charAt(0);
};
// Log the result of calling the first_last function with the argument 'a' to the console
console.log(first_last('a'));
// Log the result of calling the first_last function with the argument 'ab' to the console
console.log(first_last('ab'));
// Log the result of calling the first_last function with the argument 'abc' to the console
console.log(first_last('abc'));
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