Question

Write a while loop that replaces every occurrence of ""cat"" in the message with ""dog"" using the indexof and substring methods.

Answer 1

To replace every occurrence of "cat" with "dog" in a string, use a while loop with the indexOf and substring methods to find and replace each occurrence successively.

Step-by-step explanation:

To replace every occurrence of "cat" in a message with "dog" using a while loop, the indexof and substring methods in a programming language like Java can be utilized. An example of how this can be done is shown below:

String message = "The cat chased the cat because the cat was bored.";
int index = message.indexOf("cat");
while(index != -1) {
message = message.substring(0, index) + "dog" + message.substring(index + 3);
index = message.indexOf("cat", index + 3);
}
System.out.println(message);

In this example, a while loop is used to find each occurrence of "cat", and then replace it with "dog". The indexOf method is used to find the index of the first occurrence of "cat", and the substring method is used to reconstruct the message with "dog" in place of "cat". The search for "cat" continues from the index immediately after the replaced word to handle subsequent occurrences.

Answer 2

The program illustrates the use of loops.

Loops are used to perform repetitive and iterative operations.

The code segment where comments are used to explain each line, is as follows:

//This gets the index of "cat" in the string message

int index = message.indexOf("cat");

//The following loop is repeated, until there is no occurrence of "cat" in the string

while(index != -1){

//This replaces "cat" with "dog"

message = message.replace("cat","dog");

//This gets another index of "cat" in the string message

index = message.indexOf("cat");

//This prints the new string

System.out.print(message);

At the end of the loop, all occurrence of "cat" are replaced with "dog".

Step-by-step explanation: