so I have task to double number of letter “a” every time it occurs in a string. For example sentence “a cat walked on the road” , at the end must be “aa caaaat waaaaaaaalked on the roaaaaaaaaaaaaaaaa” . I had something like this on my mind but it doubles every charachter, not only “a”.
JavaScript
x
public static void main(String[] args) {
String s = "a bear walked on the road";
String result = "";
int i = 0;
while(i<s.length()){
char a = s.charAt(i);
result = result + a + a;
i++;
}
System.out.println(result);
}
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Answer
You need to check what the char a
is (in your case, ‘a’). Additionally, you do not repeat the characters more than twice in your code, hence not getting the answer you expected: result = result + a + a
only adds ‘a’ twice, not giving you: “aa caaaat waaaaaaaalked…”.
Here is the solution:
JavaScript
public static void main(String[] args) {
String s = "a bear walked on the road";
String result = "";
char lookingFor = 'a'; // Can change this to whatever is needed
int counter = 2;
for (int i = 0; i < s.length(); i++) {
if (s.charAt(i) == lookingFor) { // The current character is what we need to be repeated.
// Repeat the character as many times as counter is (each loop: 2, 4, 6, 8, ...)
for (int j = 0; j < counter; j++) {
result += lookingFor;
}
counter *= 2; // Double counter at every instance of 'a'
}
else { // The current char is not what we are looking for, so we just add it to our result.
result += s.charAt(i);
}
}
System.out.println(result);
}