C Programming help.

[WorldDominator]

For some reason this does like absolutely nothing. The print statement comes up and I type a random letter, but when I enter I just get an endless amount of blank lines.

 

[prolemur]

What are you going to be using this for?

Edited September 15, 2013 by prolemur

[WorldDominator]

What are you going to be using this for?

It's college work. I can't figure out why my output isn't working.

[Flojer0]

Well whats up with the scanf? it seems to have input| or something, not an array index. If you are only going to be working with one value I wouldn't even bother with an array index myself.

[WorldDominator]

Well whats up with the scanf? it seems to have input| or something, not an array index. If you are only going to be working with one value I wouldn't even bother with an array index myself.

I thought char needed a limit on its input? So that's why I put 1 there

[Flojer0]

Funny thing is, as I recall, C does nothing to babysit you. So even if you have an array there is no reason that you can't address a value outside the array. Or even negative values. But as you could imagine those are generally a very very bad ideas.

[Prince32780]

isn't the value stored in [0]

I've not coded in c for quite a while, but in a lot of other languages, you wouldn't need an array

[random314]

If you only want to grab a single character you don't need the array index on the input variable. The main problem is that you are reading input[1] this won't work because in C array indices start at 0 (so in this case input[1] will give you an undefined value as it is outside of the array)

 

You should also set the value of the input variable when you define it, otherwise it will be an undefined value until you set it to something (so there's a small chance it could be set to 'x' before you read anything).

[WorldDominator]

@Flojer0, @Prince32780, @random314 

 

I changed all the input[1] to input and initialized input as 0, but well this happens:

 

Lab3$ ./switch

Please type a character [A-Z or a-z] ('x' to exit): a

 

 

x

Segmentation fault

 

 

I tried typing a then I kept hitting enter....then I hit x just to see what happened.

[random314]

Have you replaced all occurences on input[1] with just input?

 

Also you should put a space before the conversion specifier in scanf, because it won't strip leading whitespace from the standard input.

[WorldDominator]

Have you replaced all occurences on input[1] with just input?

 

Also you should put a space before the conversion specifier in scanf, because it won't strip leading whitespace from the standard input.

Yes I did. I still get nothing

[Prince32780]

the | after input is unnecessary 

[Prince32780]

you are missing a lot of quotes

[Prince32780]

#include <stdio.h>int main (void){        char input;    input = 0;    while (input != 'x'){        printf("Please type a character [A-Z or a-z]");        printf(" ('x' to exit): ");        scanf( "%c \n", &input );//  Use switch statements to determine output        switch (input){            case 'x':            break;            case 'a' : case 'e' : case 'i' : case 'o' : case 'u' :            case 'A' : case 'E' : case 'I' : case 'O' : case 'U' :            printf("%s is a vowel\n", input);            break;            default:            printf("%s is a consonant\n", input);            break;        }    }}

this compiles, but I think something is missing

[WorldDominator]

the | after input is unnecessary 

That's not a pipe, it's just where I was last typing lol.

 

I'll see what you changed and see if it makes a difference.

 

You're missing a return 0; at the end lol. Besides that, that's exactly what I have :3

[random314]

Just noticed that the format specifiers at the bottom need to be %c not %s (%s is for a null terminated string of characters, so since it couldn't find a null it just keeps reading until it goes into some part of memory it shouldn't be in, which makes it generate a segmentation fault)

 

Like this:

#include <stdio.h>int main (void){        char input;    input = 0;    while (input != 'x'){        printf("Please type a character [A-Z or a-z]");        printf(" ('x' to exit): ");        scanf( " %c", &input );//  Use switch statements to determine output        switch (toupper(input)){            case 'x':            break;            case 'A' : case 'E' : case 'I' : case 'O' : case 'U' :            printf("%c is a vowel\n", input);            break;            default:            printf("%c is a consonant\n", input);            break;        }    }    return 0;}

[Prince32780]

why aren't you using pointers

[WorldDominator]

 

Just noticed that the format specifiers at the bottom need to be %c not %s (%s is for a null terminated string of characters, so since it couldn't find a null it just keeps reading until it goes into some part of memory it shouldn't be in, which makes it generate a segmentation fault)

I was actually playing around with that whilst I took the SS.

 

 

why aren't you using pointers

How?

 

 

Lab3$ ./switch

Please type a character [A-Z or a-z] ('x' to exit): a

s

a is a vowel

Please type a character [A-Z or a-z] ('x' to exit): s

s is a consonant

Please type a character [A-Z or a-z] ('x' to exit): d

s is a consonant

Please type a character [A-Z or a-z] ('x' to exit): c

d is a consonant

Please type a character [A-Z or a-z] ('x' to exit): f

c is a consonant

Please type a character [A-Z or a-z] ('x' to exit): ^C

Lab3$

 

^ what happens when I use all %c

[random314]

The code I posted above shouldn't have a newline in the scanf statement I've fixed it now

 

Edit: The code above runs fine, I've just tested it.

[Prince32780]

if this was java or c#, it'd be much easier

c likes to compare integers in switch statements

[WorldDominator]

The code I posted above shouldn't have a newline in the scanf statement I've fixed it now

Alright so can I not use default for all of the consonants? Because it prints is a consonant for every single one of them too.

 

 

Lab3$ ./switch

Please type a character [A-Z or a-z] ('x' to exit): a

a is a vowel

Please type a character [A-Z or a-z] ('x' to exit):

 is a consonant

Please type a character [A-Z or a-z] ('x' to exit): s

s is a consonant

Please type a character [A-Z or a-z] ('x' to exit):

 is a consonant

Please type a character [A-Z or a-z] ('x' to exit): d

d is a consonant

Please type a character [A-Z or a-z] ('x' to exit):

 is a consonant

Please type a character [A-Z or a-z] ('x' to exit):

 

[random314]

if this was java or c#, it'd be much easier

c likes to compare integers in switch statements

 

There's no need to use pointers in the switch statement, because these are single characters not strings they can be compared like integers.

[random314]

Alright so can I not use default for all of the consonants? Because it prints is a consonant for every single one of them too.

The scanf statement also needs a leading space.

 

Also you shouldn't use default for all the consonants anyway, what happens if what you type is neither a vowel nor a consonant?

[WorldDominator]

The scanf statement also needs a leading space.

 

Also you shouldn't use default for all the consonants anyway, what happens if what you type is neither a vowel nor a consonant?

OMG THANK YOU IT'S FIXED!

 

Thanks all of you, I stare at these things all day and it's always the minute details

[Prince32780]

3 is a consonant.