Problem: How to write this if-codeblock into a switch case? I have only a problem with the boolean.
int Note = 0;
Console.WriteLine("What is your note?: ");
Note = Convert.ToInt32(Console.ReadLine());
if ((Note < 1) || (Note > 6))
{
Console.WriteLine("Your input is wrong!");
}
else
{
if (Note <= 4)
{
Console.WriteLine("Passed");
}
else
{
Console.WriteLine("Failed");
}
}
I tried to write this codeblock into a switch-method.
int Note = 0;
Console.WriteLine("What ist your note?: ");
Note = Convert.ToInt32(Console.ReadLine());
switch (Note)
{
case Note < 1 || Note > 6:
Console.WriteLine("Your input is wrong!");
break;
case Note <= 4:
Console.WriteLine("Passed");
break;
}
Error Message: I can't convert the string into int.
C#7+ supports range-based switching:
switch (Note)
{
case int n when n< 1 || Note > 6:
Console.WriteLine("Your input is wrong!");
break;
case int n when n <= 4:
Console.WriteLine("Passed");
break;
}
You can do it like that if you really need a switch
switch (Note)
{
case 1:
case 2:
case 3:
case 4:
Console.WriteLine("Passed");
break;
case 5:
case 6:
Console.WriteLine("Failed");
break;
default:
Console.WriteLine("Your input is wrong!");
break;
}
This is not where switch statements are for. You should keep using if.
I will proof that very easily, using a switch, as you asked:
switch (Note)
{
case 1:
case 2:
case 3:
case 4:
Console.WriteLine("Passed");
break;
case 5:
case 6:
Console.WriteLine("Failed");
break;
default:
Console.WriteLine("Your input is wrong!");
break;
}
This is just way too verbatim. You don't want to write down every value. if is more appropriate.
Related
I want to write a code in C# that asks a user to input 2 numbers to compare which is higher but cant seem to get an output from this.
{
class Program
{
public static int Max { get; private set; }
static void Main(string[] args)
{
Console.WriteLine("Please enter 2 (two) integer numbers on a separate line: ");
int num1 = int.Parse(Console.ReadLine());
int num2 = int.Parse(Console.ReadLine());
switch (Max)
{
case 1:
if (num1 < num2)
{
Console.WriteLine(num2 + "is Maximum");
}
break;
case 2:
if (num1 > num2)
{
Console.WriteLine(num1 + "is Maximum");
}
break;
}
}
}
}
You are using the "Max" variable on the condition of the switch, but you never actually declare "Max", and the switch is only expectating the numbers 1 or 2, because you put case 1: and case 2:
So the correct way to show output is this:
if(num1 > num2)
{
Max = 1;
}
else
{
Max = 2;
}
switch(Max)
{
case 1:
Console.WriteLine(num1 + "is Maximum");
break;
case 2:
Console.WriteLine(num2 + "is Maximum");
break;
}
This is just in case you need to use a switch case, because you can do it only with a simple if
case cannot be used to compare values of two numbers you might just want to use if-else statement or if you just want a application of case statement use this :
switch (input)
{
case 1:
Console.WriteLine("a");
break;
case 2:
Console.WriteLine("b");
break;
case 3:
Console.WriteLine("c");
break;
case 4:
Console.WriteLine("d");
break;
case 5:
Console.WriteLine("e");
break;
case 6:
Console.WriteLine("f");
break;
case 7:
Console.WriteLine("g");
break;
default:
Console.WriteLine("Invalid input");
break;
}
I have the following Code down here, but when I try to add a child to parent it causes an error when parentID is bigger than 4.
public void LoadNodes()
{
ConnectionShorten("TreeViewTable");
int H = MyNodes.Tables["TreeViewTable"].Rows.Count;
for (int i = 0; i < H; i++)
{
int PID = MyNodes.Tables["TreeViewTable"].Rows[i].Field<int>("ParentID");
string Name = MyNodes.Tables["TreeViewTable"].Rows[i].Field<string>("RootName");
int Level = MyNodes.Tables["TreeViewTable"].Rows[i].Field<int>("Level");
int UID = MyNodes.Tables["TreeViewTable"].Rows[i].Field<int>("UID");
switch (Level)
{
case 0:
treeView1.Nodes.Add(Name.ToString());
break;
case 1:
treeView1.Nodes[0].Nodes.Add(Name.ToString());
break;
case 2:
switch (PID)
{
case 1:
treeView1.Nodes[0].Nodes[0].Nodes.Add(Name.ToString());
break;
case 2:
treeView1.Nodes[0].Nodes[1].Nodes.Add(Name.ToString());
break;
case 3:
treeView1.Nodes[0].Nodes[2].Nodes.Add(Name.ToString());
break;
case 4:
treeView1.Nodes[0].Nodes[3].Nodes.Add(Name.ToString());
break;
case 5:
treeView1.Nodes[0].Nodes[4].Nodes.Add(Name.ToString());
break;
case 6:
treeView1.Nodes[0].Nodes[5].Nodes.Add(Name.ToString());
break;
case 7:
treeView1.Nodes[0].Nodes[6].Nodes.Add(Name.ToString());
break;
case 8:
treeView1.Nodes[0].Nodes[7].Nodes.Add(Name.ToString());
break;
case 9:
treeView1.Nodes[0].Nodes[8].Nodes.Add(Name.ToString());
break;
case 10:
treeView1.Nodes[0].Nodes[9].Nodes.Add(Name.ToString());
break;
case 11:
treeView1.Nodes[0].Nodes[10].Nodes.Add(Name.ToString());
break;
default:
break;
}
break;
case 3:
break;
default:
break;
}
}
}
It does load 1 main node and 10 parents, then when it comes to child it says a negative index, but I'm sure the parent does exist!
Also how can I make more levels with no difficulty like this, because I think it's very difficult to make levels > 3.
You can close it, I just found that problem and solved it.
It was because there is a jump on ID on the DB. So I try to add child before I even add the parent. my program is read by ID so thats it ... sorry for this.
switch(number){
case 2:
a+=b;
break;
case 3:
a+=b;
break;
case 4:
a+=b;
d=f;
break;
case 5:
d=e;
break;
}
how to minimize first three switch cases which which does similar work?
If you using C# 7, you can make use of Pattern Matching, even though this is an overkill as rightly pointed by Jon Skeet. But in case, you want to stick to switch case, and want to reduce 'case', you could do the following
switch(number)
{
case var _ when number == 2 || number==3 || number==4:
a+=b;
if(number ==4)
d=f
break;
case 5:
d=e;
break;
}
You can also replace the first case with variants like
case var _ when new[]{2,3,4}.Contains(number):
Or
case var _ when number >= 2 || number <= 3: // As pointed by earlier answer
Without pattern matching, you could do the following as well
switch(number)
{
case 2:
case 3:
case 4:
a+=b;
if(number ==4)
d=f;
break;
case 5:
d = e;
break;
}
Btw, if your problem is "a+b" is about 60 lines of code, you always have the option to make it a function (and move it out of switch case) to increase its readability.
switch(number)
{
case 2:
case 3:
case 4:
MethodAbAction();
if(number ==4)
MethodDFAction();
break;
case 5:
MethodDEAction();
break;
}
btw, a 60 line method is never fun to read. It would be better if you can split up.
if (2 <= number && number <= 4) {
a += b;
}
if (number == 4) {
d = f;
} else if (number == 5) {
d = e;
}
if (number != 5)
{
a += b;
}
if (number == 4)
{
d = f;
}
else
if (number == 5)
{
d = e;
}
I'm working a little with switch statements and want to know how to ignore the case sensitivity when it comes to input values.
Here is my code:
using System;
namespace SwitchStatements
{
class MainClass
{
public static void Main(string[] args)
{
Start:
Console.WriteLine("Please Input the Grade");
char grade = Convert.ToChar(Console.ReadLine());
switch (grade)
{
case 'A':
Console.WriteLine("Excellent Work!");
break;
case 'B':
Console.WriteLine("Very Good Effort! Just a couple of Errors =)");
break;
case 'C':
Console.WriteLine("You Passed. Push Yourself Next Time");
break;
case 'D':
Console.WriteLine("Better put in more effort next time. I know you can do better");
break;
default:
Console.WriteLine("Invalid Grade.");
break;
}
Console.ReadKey();
goto Start;
}
}
}
If I put 'a' in instead of 'A' it returns the default response.
Can I use perhaps a .Comparison of some sort? If so where would I put it?
You can use ConsoleKey as condition for switch, the code will be like the following.
var grade =Console.ReadKey().Key;
switch (grade)
{
case ConsoleKey.A:
Console.WriteLine("Excellent Work!");
break;
case ConsoleKey.B:
// Something here
break;
case ConsoleKey.C:
// Something here
break;
case ConsoleKey.D:
// Something here
break;
case ConsoleKey.E:
// Something here
break;
default:
// Something here
break;
}
So that you can avoid converting the input to uppercase/Lower case, and then it goes for another conversion To Char. Simply use ConsoleKey Enumeration inside the switch.
You can use ToUpper(); Like
Convert.ToChar(Console.ReadLine().ToUpper());
and to get saved from the error of getting more charaters with Console.ReadLine() you can use
char grd = Convert.ToChar(Console.ReadKey().KeyChar.ToString().ToUpper());
you can use like following also
char grade = Convert.ToChar(Console.ReadLine().ToUpperInvariant());
https://msdn.microsoft.com/en-us/library/system.string.toupperinvariant.aspx
Convert to uppercase before switch like below,
grade = Char.ToUpper(grade);
Change
char grade = Convert.ToChar(Console.ReadLine());
To
char grade = Convert.ToChar(Console.ReadLine().ToUpper());
https://msdn.microsoft.com/en-us/library/system.string.toupper(v=vs.110).aspx
Write Switch on grade.ToUpper() like this and don't change change it's value, may be you will need it after
char grade = Convert.ToChar(Console.ReadLine());
switch (grade.ToUpper())
{
case 'A':
Console.WriteLine("Excellent Work!");
break;
case 'B':
Console.WriteLine("Very Good Effort! Just a couple of Errors =)");
break;
case 'C':
Console.WriteLine("You Passed. Push Yourself Next Time");
break;
case 'D':
Console.WriteLine("Better put in more effort next time. I know you can do better");
break;
default:
Console.WriteLine("Invalid Grade.");
break;
}
You may fall from one case to another like this
public static void Main(string[] args)
{
Boolean validInputRead = false;
Char grade;
while(!validInputRead)
{
validInputRead = true;
Console.WriteLine("Please Input the Grade");
grade = Convert.ToChar(Console.Read());
switch (grade)
{
case 'A':
case 'a':
Console.WriteLine("Excellent Work!");
break;
case 'B':
case 'b':
Console.WriteLine("Very Good Effort! Just a couple of Errors =)");
break;
case 'C':
case 'c':
Console.WriteLine("You Passed. Push Yourself Next Time");
break;
case 'D':
case 'd':
Console.WriteLine("Better put in more effort next time. I know you can do better");
break;
default:
Console.WriteLine("Invalid Grade.");
validInputRead = false;
break;
}
Console.ReadKey();
}
}
EDIT
Changed from Console.ReadLine() to Console.Read() as suggested
Added while(!validInputRead) as requested
string letterGrade;
int grade = 0;
// This will hold the final letter grade
Console.Write("Input the grade :");
switch (grade)
{
case 1:
// 90-100 is an A
letterGrade = "A";
Console.WriteLine("grade b/n 90-100");
break;
case 2:
// 80-89 is a B
letterGrade = "B";
Console.WriteLine("grade b/n 80-89");
break;
case 3:
// 70-79 is a C
letterGrade = "C";
Console.WriteLine("grade b/n 70-79");
break;
case 4:
// 60-69 is a D
letterGrade = "D";
Console.WriteLine(" grade b/n 60-69 ");
break;
default:
// point whic is less than 59
Console.WriteLine("Invalid grade");
break;
}
I'm creating program in which the user inputs a number that will display the month associated with that month (1 = january, 2 = feburary, 3 = march,....etc)
however, when inputting the number and pressing enter, the program breaks.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication27
{
class Program
{
public static void Main()
{
int month = 0;
//Range 1-12 refers to Month
Console.WriteLine("Please enter Month in numerical increments (1-12)");
month = int.Parse(Console.ReadLine());
switch (month)
{
case 1:
Console.WriteLine("This is the First Month...January");
break;
case 2:
Console.WriteLine("This is the Second Month...Februrary");
break;
case 3:
Console.WriteLine("This is the Third Month...March");
break;
case 4:
Console.WriteLine("This is the Fourth Month...April");
break;
case 5:
Console.WriteLine("This is the Fifth Month...May");
break;
case 6:
Console.WriteLine("This is the Sixth Month...June");
break;
case 7:
Console.WriteLine("This is the Seventh Month...July");
break;
case 8:
Console.WriteLine("This is the Eighth Month...August");
break;
case 9:
Console.WriteLine("This is the Ninth Month...September");
break;
case 10:
Console.WriteLine("This is the Tenth Month...October");
break;
case 11:
Console.WriteLine("This is the Eleventh Month...November");
break;
case 12:
Console.WriteLine("This is the Twelfth Month...December");
break;
default:
Console.WriteLine("You have inputed an invalid Character");
break;
}
//Attempt to looP code
}
}
}
Unsure what is causing the termination
Add a while loop to your code and set a code like "0" to exit the loop or terminate the program.
public static void Main()
{
int month = 0;
bool exit = false;
while (!exit)
{
//Range 1-12 refers to Month
Console.WriteLine("Please enter Month in numerical increments (1-12)");
month = int.Parse(Console.ReadLine());
switch (month)
{
case 0:
exit = true;
break;
case 1:
Console.WriteLine("This is the First Month...January");
break;
case 2:
Console.WriteLine("This is the Second Month...Februrary");
break;
case 3:
Console.WriteLine("This is the Third Month...March");
break;
case 4:
Console.WriteLine("This is the Fourth Month...April");
break;
case 5:
Console.WriteLine("This is the Fifth Month...May");
break;
case 6:
Console.WriteLine("This is the Sixth Month...June");
break;
case 7:
Console.WriteLine("This is the Seventh Month...July");
break;
case 8:
Console.WriteLine("This is the Eighth Month...August");
break;
case 9:
Console.WriteLine("This is the Ninth Month...September");
break;
case 10:
Console.WriteLine("This is the Tenth Month...October");
break;
case 11:
Console.WriteLine("This is the Eleventh Month...November");
break;
case 12:
Console.WriteLine("This is the Twelfth Month...December");
break;
default:
Console.WriteLine("You have inputed an invalid Character");
break;
}
}
//Attempt to looP code
}