switch statements with <?

[dmc333]

I have a program where I ask a user to input their income and then it evaluates the
tax using switch statements. The program ends where I enter the income and fails to show me the tax.

Here's some of the code:

case 1: if (income < 1000) tax = income*.3;
printf("\nYou have this much: %lf in taxes", tax);
break;

Thanks

[oler1s]

This program is very small in size. Post the entire thing.

Read up on switch statements. You should see that the integral value is evaluated in the switch(...) syntax, and the case statements deal with the various possibilities.

Here's a hint. You can consider a boolean an integral value. A < comparison is either true or false. False is considered to be 0 and 1 is considered to be true. So, what would you be putting in the switch input?

[lumpybanana247]

try this [i just compiled it and it works fine]

#include <iostream>
using namespace std;
double income=31320;
double tax;
int main()
{
if (income < 1000){ tax = income*.3;}
else if (income < 2000){ tax = income*.4;}
else if (income < 3000){ tax = income*.5;}
else if (income > 3999){ tax = income*.9;}
printf("\nYou have this much: %lf in taxes", tax);
cin.get();
return 0;
}

[dmc333]

I had income as the switch variable. I think I remember my instructor talking about
using an A variable. If A= even, then A is true, or A=odd , then A is false. Something like that. I know how to make this program with if statements, but I need to use switch. If someone could give me a link to an example similar to my program, that would be great. I tried google, but I found nothing using something similar. And nothing in my book either.

Here is what tried:

#include <stdio.h>

int main(void)
{

int income;
double tax;

printf("Please input your income here->");
scanf("%d", &income);

switch(income)
{
case 1: if (income < 1000) tax = income*.2;
printf("\nYou have this much: %lf in taxes", tax);
break;
case 2: if (income >= 1000 && income < 2000) tax = income*.3;
printf("\nYou have this much: %lf in" "taxes\n", tax);
break;
case 3: if (income >= 2000) tax = income*.4;
printf("\nYou have this much: %lf in taxes\n", tax);
break;
}
}

And my output:

Please input your income here->2100
It ends not getting the answer.

[thenath24]

I had income as the switch variable. I think I remember my instructor talking about
using an A variable. If A= even, then A is true, or A=odd , then A is false. Something like that. I know how to make this program with if statements, but I need to use switch. If someone could give me a link to an example similar to my program, that would be great. I tried google, but I found nothing using something similar. And nothing in my book either.

Here is what tried:

#include <stdio.h>

int main(void)
{

int income;
double tax;

printf("Please input your income here->");
scanf("%d", &income);

switch(income)
{
case 1: if (income < 1000) tax = income*.2;
printf("\nYou have this much: %lf in taxes", tax);
break;
case 2: if (income >= 1000 && income < 2000) tax = income*.3;
printf("\nYou have this much: %lf in" "taxes\n", tax);
break;
case 3: if (income >= 2000) tax = income*.4;
printf("\nYou have this much: %lf in taxes\n", tax);
break;
}
}

And my output:

Please input your income here->2100
It ends not getting the answer.

Reply:

The program is not giving you any output because your variable does not meet one of your case conditions.

For example for you program to evaluate a salary under 1000 at the moment you would have to enter 1 when asked to enter your income, clearly this is not what you are trying to achieve.

In a switch case statement the variable you provide (in this case income) is what dictates which case is processed.

There may be a better way of doing it but off the top of my head something like this would work;

if(income <1000)
{
//set flag
dummyInt = 1;
}

//code to calcualte tax

switch(income)
{
case 1:
printf("\nYou have this much: %f in taxes", tax);
break;

}

[oler1s]

Asides: a reminder to use CODE tags around portions of code. It makes the code readable, which in turn allows us to help you. If you present code in an unreadable mess here, we will simply ignore your post, because we will not attempt to read unreadable code.

lumpybanana: You miss the point of dmc's assignment. The idea is to use switch statements, which obviously your code doesn't. Besides, do not spoon feed code to other people. That defeats the purpose of your presence here.

thenath: You made crippling mistakes in your attempt, but your idea is far more complicated than it should be.

Now, on to dmc's issue at hand. Dmc, there is no direct example here. This isn't a syntax question anymore. Well it is, but really, it's a logic game, and there's no point in us giving you the answer. So, as frustrating as it might be, we'll push you to figure out the answer on your own. My first reply had a major hint. I'll explain further.

I had income as the switch variable.

Ok. Now consider the values income can be. It can be 1. It can be 20. It can be 1000. It can be 500000. It can be anything. What you want to do is determine if income is one of three ranges (<1000, 1000-2000, and >=2000), which is equivalent to saying you have three different cases. Do you see where I'm going with this? Testing the input doesn't make sense, as you don't actually care what value the input is. Let's say the income is less than 1000. Does it matter if it is 999 vs 998? No. So obviously, testing input directly gets you nothing. If you followed what I said above, it's obvious your three cases are the three ranges income can fall into. It's easy to write them as if statements, but the question how can you represent three if comparisons as switch statements.

Now, look at my first reply. Consider 5 < 10. What is the value of 5 < 10? It's true. What about 7 < 5? False. What about representing true and false as integral values. Remember true and false can be thought of as 1 and 0. And also recall that the switch variable must be an integral value. Now, what could you possible use for the switch, given that you want to check for those three cases?

[sridharvaradarajan]

void main()
{
int income,choice = 0;
double tax;

printf("1.Tax calculation \n 2.addition ");
printf("\n enter the choice:");
scanf("%d",&cho ice);

switch(choice)
{
case 1:
printf("\nenter the income:");
scanf("%d",&inc ome);
if (income < 1000)
tax = income * 0.3;
printf("\nYou have this much: %lf in taxes", tax);
break;
case 2:
printf("\naddit ion");
default:
printf("\nthe nu,ber u have entered is invalid");
}
}

U just use this program it will work fine.. Because switch statements wont allo to evaluate any expression in case conditions. it needs only constants.