JavaScript: Check a given string contains 2 to 4 numbers of a specified character

JavaScript Basic: Exercise-35 with Solution

Write a program to check whether a specified character exists between the 2nd and 4th positions in a given string.

The program checks if a specified character is present in a given string between the 2nd and 4th positions (i.e., indices 1 to 3). It returns true if the character exists in that range and false otherwise.

Sample Solution:

JavaScript Code:

// Define a function named check_char with parameters str1 (a string) and char (a character)
function check_char(str1, char)
{
  // Initialize a counter variable to 0
  let ctr = 0;

  // Use a for loop to iterate through each character in the string
  for (let i = 0; i < str1.length; i++)
  {
    // Check if the current character is equal to the specified char and if the index is between 1 and 3 (inclusive)
    if ((str1.charAt(i) == char) && (i >= 1 && i <= 3))
    {
      // Set the counter to 1 and break out of the loop
      ctr = 1;
      break;
    }
  }

  // Check if the counter is 1 and return true, otherwise return false
  if (ctr == 1) return true;
  return false;
}

// Log the result of calling check_char with the arguments "Python" and "y" to the console
console.log(check_char("Python", "y"));

// Log the result of calling check_char with the arguments "JavaScript" and "a" to the console
console.log(check_char("JavaScript", "a"));

// Log the result of calling check_char with the arguments "Console" and "o" to the console
console.log(check_char("Console", "o"));

// Log the result of calling check_char with the arguments "Console" and "C" to the console
console.log(check_char("Console", "C"));

// Log the result of calling check_char with the arguments "Console" and "e" to the console
console.log(check_char("Console", "e"));

// Log the result of calling check_char with the arguments "JavaScript" and "S" to the console
console.log(check_char("JavaScript", "S")); 

Output:

true
true
true
false
false
false

Live Demo:

See the Pen JavaScript: check a given string contains 2 to 4 numbers - basic-ex-35 by w3resource (@w3resource) on CodePen.

Flowchart:

ES6 Version:

// Define a function named check_char using arrow function syntax with parameters str1 and char
const check_char = (str1, char) => {
  // Initialize a counter variable to 0
  let ctr = 0;

  // Use a for loop to iterate through each character in str1
  for (let i = 0; i < str1.length; i++) {
    // Check if the current character equals char and the index is between 1 and 3 (inclusive)
    if (str1.charAt(i) === char && i >= 1 && i <= 3) {
      // Set the counter to 1 and break out of the loop
      ctr = 1;
      break;
    }
  }

  // Check if the counter is 1 and return true, otherwise return false
  return ctr === 1;
};

// Log the result of calling check_char with the arguments "Python" and "y" to the console
console.log(check_char("Python", "y"));

// Log the result of calling check_char with the arguments "JavaScript" and "a" to the console
console.log(check_char("JavaScript", "a"));

// Log the result of calling check_char with the arguments "Console" and "o" to the console
console.log(check_char("Console", "o"));

// Log the result of calling check_char with the arguments "Console" and "C" to the console
console.log(check_char("Console", "C"));

// Log the result of calling check_char with the arguments "Console" and "e" to the console
console.log(check_char("Console", "e"));

// Log the result of calling check_char with the arguments "JavaScript" and "S" to the console
console.log(check_char("JavaScript", "S"));

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