Write multiple things in a switch statement in C

Question

So i need to have my switch statement go through and write out five two if the user says 52 but i cannot get it pass my 0-9. if they type 0-9 it works perfect but if i try to do any number past that it makes a blank. help!

#include <stdio.h>

int main (void)
{

        int x;

        printf("Please enter an integer: ");
        scanf("%d", &x);

        printf("\nYou have entered:\n\n");

        for(x;x<0;x++);

        switch (x)

        {
        case 0:
                printf("zero");
                break;
        case 1:
                printf("one");
                break;
        case 2:
                printf("two");
                break;
        case 3:
                printf("three");
                break;
        case 4:
                printf("four");
                break;
        case 5:
                printf("five");
                break;
        case 6:
                printf("six");
                break;
        case 7:
                printf("seven");
                break;
        case 8:
                printf("eight");
                break;
        case 9:
                printf("nine");
                break;
        }

        printf("\n\n");



        return 0;
}

Homework, right? You might want to try writing out in words what you need to do and figure out how to take those words and turn them into code. — plinth, Nov 07 '13 at 18:14
The line `for(x;x<0;x++);` probably doesn't do what you think it does. — Adam Liss, Nov 07 '13 at 18:15
(Hints rather than code since this is homework) You could convert `x` to a string using `sprintf`, then loop over the characters in the string, using your switch statement for each one. — simonc, Nov 07 '13 at 18:15
i have not learned sprintf so i won't use it. i'm trying to think around the ways we have learned but its not easy. — user2963635, Nov 07 '13 at 18:26

Sorin · Answer 1 · 2013-11-07T22:15:23.707

3

do {
  switch (x%10) {
    ...
  }
  x = x / 10;
} while (x>0) ;

or to get it in the right order use recursion

void f(int x) {
  if (x==0) return;
  f(x/10);
  switch(x%10) { ... }
}

edited Nov 07 '13 at 22:15

answered Nov 07 '13 at 18:16

Sorin

11,863
22
26

5

For input `52` the user wants the output `five two`. This would print `two five` wouldn't it? – masotann Nov 07 '13 at 18:21
1

The special case could be solved with a do-while instead of a while, so it will always run once. – geekster777 Nov 07 '13 at 18:25
Yes it will output the digits with the least significant first. But the question is not explicit about the order. – Sorin Nov 07 '13 at 18:27
Thanks @geekster777. I made it a do-while. No need to special case 0. – Sorin Nov 07 '13 at 18:28
yeah i got that far but it does print out second number first. how would i combat that? – user2963635 Nov 07 '13 at 22:08
how can i switch the statement to read from left to right in this order 52 to read five two? – user2963635 Nov 07 '13 at 22:15
after i tried that if statement it just gives me the second number of the two numbers. – user2963635 Nov 07 '13 at 22:23

score 0 · Answer 2 · edited May 23 '17 at 11:50

0

This question has been asked-and-answered before.

The for-loop you wrote is empty, because the body of the loop ends with the semi-colon:

for(x;x<0;x++) /* Empty Body!!*/ ;

The way a typical for loop works is:

for( /*Initialize*/;  /*Test*/;  /*Change*/)
{
    /* Body */
}

In your case, I think you want:

for(int i=0;  i < x; ++i)
{
    switch(x)
    {
         [...]
    }
}

This will:

Initialize i to 0
Test if i is LESS THAN x (the number you entered)
Keep increasing i by 1, until it gets up to x.

edited May 23 '17 at 11:50

Community

1
1

answered Nov 07 '13 at 18:15

abelenky

63,815
23
109
159

the for loop i put in there is just something i tried to get it to work. i thought that when i put in like 15 if will find one but i need to loop it so it also picks out the five. thats where i'm running into my problems. keep in mind i'm a very base level student and i haven't learned a lot of things that would make this easier. – user2963635 Nov 07 '13 at 18:19
You can see my answer to a similar question at: http://stackoverflow.com/questions/16967008/how-to-get-different-digits-starting-from-the-most-significant-digit-in-a-number – abelenky Nov 07 '13 at 18:23

score 0 · Answer 3 · edited May 23 '17 at 12:29

0

Here's what you need to do. Similar to what @simonc said, it's a good idea to convert the user input to a string, then loop through the characters. For each character, convert it into an int and then take that into the switch statement.

EDIT---------------------------

Here's a way with strictly using integers.

First find how many digits your integer has. You can do this by a method mentioned here.

Then do integer division starting from the largest power of 10 that divides the integer you have and divide the divisor by 10 until you reach 1. For example:

If user input is 213, it has 3 digits. We divide this by 100 first. 213/100 = 2

We take the 2 and put it into the switch statement, outputting 2. Now we're done with the hundreds digit, so now we take the 13 from 213 and divide it by 10.

13/10 = 1 So now we output one.

Keep doing this process until you get to the ones digit.

Does this make sense?

edited May 23 '17 at 12:29

Community

1
1

answered Nov 07 '13 at 18:20

masotann

901
10
29

not really i guess. sorry this is really tough stuff to learn. :O – user2963635 Nov 07 '13 at 18:22
@user2963635 mm which part are you confused? i'll edit the answer to your needs – masotann Nov 07 '13 at 18:22
is string like a way of commands? if so i have not learned that yet and probably shouldn't be putting down things i haven't learned. and by character do you mean case? – user2963635 Nov 07 '13 at 18:25
by string, i mean the string class. It's an array of characters (which is a `char` class). You have not yet seen the `char` or `string` classes? – masotann Nov 07 '13 at 18:25
i've had char but i have not had string. – user2963635 Nov 07 '13 at 18:31

geekster777 · Answer 4 · 2013-11-07T18:30:26.427

0

You could solve this with recursion.

void printDigit(int x) {

  int digit = x%10;
  if(digit!=x)
    printDigit(x/10);
  switch(digit) {
  ...
  }
}

This will print the most significant figure first, unlike the while loops most people are mentioning.

edited Nov 07 '13 at 18:30

answered Nov 07 '13 at 18:21

geekster777

297
1
5

score 0 · Answer 5 · answered Nov 07 '13 at 18:24

I'm not going to do your homework for you but consider the following pseudo-code:

print_text_digits(x)
{
    if (x >= 10) print_text_digits(x / 10);
    switch (x) {
        print "zero" through "nine" as appropriate
    }
}

main()
{
    scan number into x;
    print_text_digits(x);
}

This relies on a recursive routine so that you get your digits processed one at a time, with the might significant digit printed first.

score 0 · Answer 6 · answered Nov 07 '13 at 18:42

I believe you need this:

#include <stdio.h>

int main (void)
{

int count = 0;
int x, count2;

printf("Please enter an integer: ");
scanf("%d", &x);

printf("\nYou have entered:\n\n");

int aux = x;
while(aux>0) {
    aux=aux/10;
    count++;
}
count2 = count;
while(count) {
    aux = x;
    for(int i=count-1;i>0;i--)
        aux=aux/10;
    for(int i=count2-count;i>0;i--)
        aux%=10;
    switch (aux) {
        case 0:
            printf("zero");
            break;
        case 1:
            printf("one");
            break;
        case 2:
            printf("two");
            break;
        case 3:
            printf("three");
            break;
        case 4:
            printf("four");
            break;
        case 5:
            printf("five");
            break;
        case 6:
            printf("six");
            break;
        case 7:
            printf("seven");
            break;
        case 8:
            printf("eight");
            break;
        case 9:
            printf("nine");
            break;
    }
    count--;
    if(count) printf(" ");
}
printf("\n\n");
return 0;
}

Now, with an input 52 it will propelly return five two.

score 0 · Answer 7 · answered Nov 07 '13 at 20:31

#include <stdio.h>

static const char * const num[] = {
    "zero ", "one ", "two "  , "three ", "four ",
    "five ", "six ", "seven ", "eight ", "nine "
};

void printNum(int x)
{
    if (x < 10) {
        printf(num[x]);
        return;
    }
    printNum(x / 10);
    printNum(x % 10);
}

int main (void)
{
    int x;

    printf("Please enter an integer: ");
    scanf("%d", &x);

    printf("\nYou have entered:\n\n");

    printNum(x);
    return 0;
}

what you are doing what is it called. – user2963635 Nov 07 '13 at 22:41 — user2963635, Nov 07 '13 at 22:41

Write multiple things in a switch statement in C

7 Answers7