Help converting an int to a char?

[motionman95]

I just started using C, and I'm still learning, so I guess that makes me a noob.
Anyway, what I've been trying to do is store and int variable in a char variable. After reading about the sprintf() function, I tried this:

int cur_num = 15;
char buff[50];
char code[50];

static void make_code_string(void) {
	sprintf(buff, "%d", cur_num);
	code = code + buff;
}

But I keep getting

error: invalid operands to binary +

Help please?

[tabstop]

What do you want code = code + buff to do? Do you want to add 15 to code? If so, then just do so:

code = code + 15;
or
code = code + cur_num;

If you want to do something else, then you'll have to actually state what you want.

(Note also that

code = code + 15;

is the same as

code += 15;

[motionman95]

I tried that, but I got:

error: incompatible types in assignment

[tabstop]

Ah: code and code[50] are most definitely not the same thing. If you want to add to the end of a string, you use strcat. Note that code must be a legitimate (i.e., \0 terminated) string to begin with.

[motionman95]

Would this be considered a legitimate string?

legitimate_string[50] = "Is this a legitimate string?\0"

[tabstop]

Anything in "double quotes" is a legitimate string, even without the explicit \0.

[motionman95]

I don't get it. This code is perfect yet I keep getting the "warning: passing argument 2 of 'sprintf' makes integer from pointer without a cast" and "warning: passing argument 3 of 'sprintf' makes integer from pointer without a cast" errors. Whats wrong??!!

int cur_num = 1;
char buff[50];

sprintf(buff, "%d", cur_num);

[tabstop]

If you don't have #include <stdio.h> at the top, you don't have sprintf.

And are you sure that's the code you're dealing with? Argument 3, as you have it, is cur_num which is an integer, so you can't possibly be converting from a pointer.

[motionman95]

Thanks for the help! I've figured it out.

[motionman95]

One last question: how do you empty a char variable? This doesn't work:

char string[] = "";

[laserlight]

What do you mean by "empty a char variable"? Your example initialises a string named string to an empty string.

[motionman95]

I'm meant this:

char string[50] = "This string is really filled dynamically filled.";

And after I've filled "string" and am ready to use it again, I want to empty it, but this isn't working:

char string[] = "";

[laserlight]

Oh, in that case you call just null terminate it at the start, i.e.,

string[0] = '\0';

Actually, why not just use it immediately? You will be replacing the contents with another string, anyway.

[motionman95]

I need to empty it first because I am using strcat to fill it. What should I do?

[laserlight]

In that case my example should suffice.