Replacing multiple words in a string sentence C#

Question

Hello guys, I don't need the answer but I would look to know and find out what I'm doing wrong. As a beginner I got a very "easy" assignment in my studies. I need to create a string and inside this string I need to replace some words by other words without using the for loop as so: ( also I want to print it but I got no clue where to put Console.WriteLine and google searching for 1 hour didn't work or asking a colleage.

/* Excersice: use with stringbuilder * cat becomes littlecat * dog becomes littledog * mouse becomes littlemouse * words the must be replace by a * do not use a loop*/

using System;
using System.Collections.Generic;
using System.Text;

namespace Opgavens_leerpad_3_oefening
{
    class Program
    {
        static string Main(string[] args)
        {
            StringBuilder sb = new StringBuilder();

            string dogCat = new string("Can the cat find the mouse without waking the dog.");

            static string replacethisstring(string dogCat);
            {
                hondKat = dogCat.Replace("cat", "littlecat");
                hondKat = dogCat.Replace("dog", "littldog");
                hondKat = dogCat.Replace("mouse", "littlemouse");
                hondKat = dogCat.Replace("the", "a");
                return dogCat;
            }
        }
    }
}

Error CS5001: Program does not contain a static "Main" method suitable for an entry point ( I don't get this doesn't almost any program starts with this static Main args? )

Error CS8112: replacethisstring(string)' is a local function and must therefore always have a body. ( I just gave it a body right? I opened the { and close it } and put a replace with return. )

Answer 1

The method declaration ends with ; that's the reason for CS8112

The Main method has to return void (or 'int' )you've modified it to string , that's the reason for CS5001

If you want the program to print the output on the console use:

using System;

....

 Console.WriteLine(output)

Answer 2

1. Your main should have a void as return type. string is not allowed but int is an option ( see reference )
2. You cannot have ; at the end of a function declaration that has a body to it.
3. You have to declare a variable before you can use it ... string hondKat;
4. See the use of StringBuilder in the below code instead of string.

namespace Opgavens_leerpad_3_oefening
{
    class Program
    {
        public static void Main(string[] args)
        {
            StringBuilder sb = new StringBuilder();

            sb.Append("Can the cat find the mouse without waking the dog.");
            sb = replacethisstring(sb);

            Console.WriteLine(sb.ToString());
            Console.ReadLine(); // To Stop the Console from closing.

            static StringBuilder replacethisstring(StringBuilder dogCat)
            {
                dogCat = dogCat.Replace("cat", "littlecat");
                dogCat = dogCat.Replace("dog", "littldog");
                dogCat = dogCat.Replace("mouse", "littlemouse");
                dogCat = dogCat.Replace("the", "a");
                return dogCat;
            }

        }
    }
}

You can place the function within the Main or outside. Normally you would find functions outside of the Main class.

    public static void Main(string[] args)
    {
    ...
    }

    public static string replacethisstring(string dogCat)
    {
    ...
    }

Answer 3

Having several issues like typos, syntax error etc. Additionally, the excercise having a condition that needs to use with stringbuilder.

So, try this.

    static void Main(string[] args)
    {
        StringBuilder sb = new StringBuilder("Can the cat find the mouse without waking the dog?");
        sb = replacethisstring(sb);

        Console.WriteLine(sb.ToString());
        Console.ReadLine();
    }

    static StringBuilder replacethisstring(StringBuilder dogCat)
    {
        StringBuilder hondKat = dogCat.Replace("cat", "littlecat");
        hondKat = dogCat.Replace("the", "a");
        hondKat = dogCat.Replace("dog", "littledog");
        hondKat = dogCat.Replace("mouse", "littlemouse");
        return hondKat;
    }