Thread: Beginner Help

Im barely learning C at my high school and I was wondering is there a way to print "\" and is there a way to compare a char string with a character.

What I mean is having a word and compare by a letter.

To print a backslash you must put a doublequote before it:

Code:

printf(""\");

The strncmp function can be used to compare the first n characters of two strings and returns 0 if same, <0 if less than (alphabetically), and >0 if more than, so for example:

Code:

#include <string.h>

int compareFirstLetter() {
    char *yourWord = "hello";
    return strncmp(yourWord, "h", 1);
}

would return 0. However that example doesn't compare the whole word, just the first letter.


are you using a book for learning C? there should be some kind of reference/appendix that gives an overview of the string.h library functions (where strncmp comes from)

Originally Posted by space-oddity

To print a backslash you must put a doublequote before it:

Code:

printf(""\");

The strncmp function can be used to compare the first n characters of two strings and returns 0 if same, <0 if less than (alphabetically), and >0 if more than, so for example:

Code:

int compareFirstLetter() {
    char *yourWord = "hello";
    return strncmp(yourWord, "h", 1);
}

would return 0. However that example doesn't compare the whole word, just the first letter.

I think you are missing a end quote and I need the whole word to be compared.Would it work in a loop?

int compareFirstLetter() {
char *yourWord = "hello";
int counter;
for(counter=0;counter<strlen(yourWord);counter++)
{
strncmp(yourWord, "h", counter);
}

missing an endquote? if you want to print a backslash you just put one doublequote before it:

Code:

printf("Printing a backslash: "\ Done.");

you want to compare the whole word with just one letter? what are you specifically wanting to check for? but yes, a loop will be required for something like that. (Unless you're dealing with just one word and you know how long that word will be, allowing you to use a multiple of that one letter ("hello" and "aaaaa") but that's unlikely.)

do you know about the manual? type man printf or man strncmp or man "name of function" into your shell to find some useful information

actually you don't have to use strncmp if you're just comparing for equality to one letter (but you don't know whether it's less than or greater than if it isn't equal). you can do something like:

Code:

int i = 0;
char *yourWord = "Hello";
while (yourWord[i] != '\0'){
    if (yourWord[i] == "a") {
        /*...do something...*/
    }
    i++;
}

that goes through all the letters of the word checking if it is the letter a, and if so does something..

there's some useful tutorials on this site if you want to look, http://www.cprogramming.com/tutorial.html

Originally Posted by maniac20

For me this is not working im getting "undefined reference to `WinMain@16' " error.

You have your compiler set up to compile the program as a windows program. You need to change your compiler's settings so it compiles as a console program. int main() is the first function a console program starts with, WinMain() is the first function a windows program starts with.

Originally Posted by space-oddity

To print a backslash you must put a doublequote before it

Actually, you would use a backslash before it, not a double quote. The double quote will make the compiler think you've ended your text string and that is not what you want.

The backslash in a string makes the character immediately following it behave differently:

Code:

printf("\\"); /* prints \ */
printf("\");  /* this is an error, there is no ending quote for the string */
printf("\""); /* prints " */
printf(""");  /* (note: 3 double quotes in a row) is an error.  */
printf("\t"); /* prints the tab character */
printf("t");  /* prints t */
printf("\0"); /* prints the NULL character */
printf("0");  /* prints 0 */
etc.

I think space-oddity has things backwards.

To print a backslash you must put a doublequote before it:

Code:

printf(""\");

Actually, to print a backslash, one would use:

Code:

printf("\\");

You see, the compiler starts processing a string when it finds a double quote. It stops processing the string when it finds another double quote. If you want to put a double quote inside a string, therefore, you have to use \". Since the backslash is used to "escape" characters like this, to include a literal backslash you must escape the backslash itself with \\.

I'm probably just being confusing. http://www.cppreference.com/escape_sequences.html

[edit] Beaten. [/edit]

The easiest thing would probably be to encapsulate the game itself into a separate function, then in main() you would run a loop until the user entered no (response to "Play again?"). Each time through the loop you would call the function that runs the game.

Something like:

Code:

int main()
{
  char yn = 'y';

  while (yn == 'y')
  {
    play_game();
    printf("Play again? (y/n)");
    scanf("%c", &yn);
  }

  return 0;
}

[edit]too slow. [/edit]