Get rid of space, use scanf or getchar. Which is better?

[jjohan]

Hi,

I want the user to be able to enter a command then a character, like for example:

push r

I want the command to be stored in the array command, and the character to be stored in the variable c.

Now I wonder what the best way to get rid of the space is, using scanf or getchar (see below for code, only thing that I changed between the 2 versions is the statement before the comment "get rid of space")? Or maybe it doesnt matter?

include <stdio.h>
#define MAX 200

void push(char c);       // Puts a new element last in queue
char pop(void);            // Gets the first element in queue

static char s[MAX];


int main(void)
{
    char c;
    char command[10];
    
    printf("Enter push character to put a new element in in queue. Enter pop to retrieve firs element in queue:\n");
    scanf("%s", command);
   
    scanf("%c", &c);    // Get rid of space
    scanf("%c", &c);
    
    printf("command: %s\n", command);
    
    printf("Element: %c\n", c);
    
    return 0;
    
}

include <stdio.h>
#define MAX 200

void push(char c);       // Puts a new element last in queue
char pop(void);            // Gets the first element in queue

static char s[MAX];


int main(void)
{
    char c;
    char command[10];
    
    printf("Enter push character to put a new element in in queue. Enter pop to retrieve firs element in queue:\n");
    scanf("%s", command);

    getchar();                         // Get rid of space
    scanf("%c", &c);
    
    printf("command: %s\n", command);
    
    printf("Element: %c\n", c);
    
    return 0;
    
}

Thanks if you want to help.

[stahta01]

This is bad.

    scanf("%c", &c);    // Get rid of space
    scanf("%c", &c);

Change it to this and it is best!

    scanf(" %c", &c);    // skip leading space

Tim S.

[Matticus]

You can get the string and the character in one line:

scanf("%s %c", command,&c);

This would also eliminate a potential problem with your initial code, if the user enters more than one space between the command and the character.

For truly robust input handling, though, I'd suggest reading the entire input with "fgets()" and parsing the string as needed.

[c99tutorial]

If you just want to ignore spaces, you can place a space character in the format string to scanf. This will skip over 0 or more whitespace characters, so user can type "push a" or "push a" and the result will be the same. Example

scanf(" %d", &x); // skip over whitespace and then read in an int and store it in location &x

[jjohan]

Thank you all for giving good advice!

[stahta01]

If you just want to ignore spaces, you can place a space character in the format string to scanf. This will skip over 0 or more whitespace characters, so user can type "push a" or "push a" and the result will be the same. Example

scanf(" %d", &x); // skip over whitespace and then read in an int and store it in location &x

Please try NOT to post this stuff; the only time that a space really seems to help is in front of a %c in all other cases it normally does nothing useful.

FYI: The %d skips over white-spaces by default!

Tim S.

[Click_here]

If you just want to ignore spaces, you can place a space character in the format string to scanf. This will skip over 0 or more whitespace characters, so user can type "push a" or "push a" and the result will be the same. Example

scanf(" %d", &x); // skip over whitespace and then read in an int and store it in location &x

A trailing new line character does not affect an integer input, only character input.

[edit]
Beaten to replying again - Today is not my day!
[/edit]