function in C to print char content

Question

I'm trying to create a function in C to print the content of the char variable.

Here is my code for the function itself:

void printChar(char ChArr[])
{
    int iCharLen = sizeof(ChArr); // define ChArr[] length
    int i;
    for(i = 0; i<iCharLen; i++)
    {
        printf("%c",ChArr[i]);
    }     
}

Here is the code for "int main()":

int main()
{  
  char ChAr[] = "A very long char!!!!";
  printChar(ChAr[]);  
  return 0;
}

And the error I got is: "error: expected expression before ']' token"

The error is for line where I call the printChar().

Note: This code is for C only.

This code is broken on so many levels, you should probably pick up a text book on C or at least take some tutorials first. To fix the compilation error you need to remove the [] after ChAr, but the code won't do what you want anyway (hint sizeof does not work that way). — Bishop, Jul 14 '13 at 10:19

score 3 · Answer 1 · edited May 23 '17 at 12:11

When you declare:

char ChAr[] = "A very long char!!!!";

the default size of ChAr[] array is the size of the string you used in the definition/initialization of the array.

After that, in any expression ChAr[] is not a valid, and you have to give some index value within []; this the reason you are getting an error like:

"error: expected expression before ']' token"

It means, in call of function:

printChar(ChAr[]); 
               ^  before ] you are missing some index value

Additionally, even if you call it like printChar(ChAr[i]); it won't compile (not correct) and will give a type mismatch error. According to your function declaration below:

void printChar(char ChArr[]){
                    ^ you need an char*

you should call this function as:

printChar(ChAr);

Because type of ChAr is char[N] which is what the function printChar accepts as an argument.

Next error in function printChar() is that evaluating length of string using sizeof operator is wrong; use strlen() instead of sizeof operator. That means:

 int iCharLen = sizeof(ChArr); // define ChArr[] length

should be:

 int iCharLen = strlen(ChArr); // define ChArr[] length

Don't forget to #include <string.h>.

Remember in function declaration char ChArr[] is same as char* ChArr.

The sizeof() operator returns size of array only if an array name is given, but in your function you are passing the address of char* that doesn't return length of your string; instead, it gives sizeof pointer variable ChAr (usually 4 bytes or 8 bytes).

To understand how sizeof() operator works in both case read: What does sizeof(&arr) return?

Thx for explanation! Understood the mistake. Fixed it. Now Works — Ryu Akira Kenshin Yuki, Jul 14 '13 at 11:26
@JonathanLeffler Thanks to fix my trivial typos. I notice [revision](http://stackoverflow.com/posts/17638597/revisions) carefully, I will take care/ improve my answers. — Grijesh Chauhan, Jul 14 '13 at 19:39

Nithin Bhaskar · Accepted Answer · 2013-07-14T10:23:13.280

2

Remove the [] when passing the character array to the function. Hence your function call will look like this:

printChar(ChAr);

This will solve the compiler error.

In addition, use strlen(ChArr) in the function definition instead of sizeof(ChArr).

Only then will all the characters in the array be displayed.

edited Jul 14 '13 at 10:23

answered Jul 14 '13 at 10:17

Nithin Bhaskar

686
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9

score 1 · Answer 3 · answered Jul 14 '13 at 10:17

1

Drop the [] when calling the function:

printChar(ChAr);

Also, sizeof in the function will return the size of a pointer to char, not the number of chars in the array. This is probably not what you expected.

answered Jul 14 '13 at 10:17

Joni

108,737
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Saxtheowl · Answer 4 · 2013-07-14T22:47:00.290

you can also do a my_putchar func, here it is:

void my_putchar(char c)
{
write(1, &c, 1);
}

int main()
{
my_putchar('a'); // for example
}

and with that you can also more fancy stuff like my_putstr or my_puts func

void my_putstr(char *str)
{
int i;

i = 0;
while(str[i] != '\0')
{
my_putchar(str[i]);
i++;
}
}

or more short

void my_putstr(char *str)
{
write(1, str, strlen(str));
}

it can do:

int main()
{
my_putstr("abcdef");
}

hope this help you :)

function in C to print char content

4 Answers4