"warning: passing argument 2 of ‘strcat’ makes pointer from integer without a cast"

Hi, all--
I'm writing a program to find the longest common prefix of two words (e.g. input "department" and "depart", get "depart" back; input "global" and "glossary", get "glo" back), and when I attempt to compile, I get the above warning. Here's my code, with the line in question in red:

Code:

#include <stdio.h>
#include <string.h>

int main()
{
	char one[11], two[11], prefix[11];
	int i = 0, len;
	printf("Please enter two words: ");
	scanf("&#37;s%s", one, two);
	
	if(strlen(two) < strlen(one))
	{
		len = strlen(two);
	}//if(strlen(two) > strlen(one))
	else
	{
		len = strlen(one);
	}

	while(one[i]==two[i] && i < len)
	{
		strcat(prefix, one[i]);
		i++;
	}//while one[i]==two[i] -- tests each letter of one and two, and if they're the same, appends letter to prefix

	printf("The longest common prefix of %s and %s is %s.", one, two, prefix);
	return 0;

}//main

I'm not sure what I'm doing wrong or how to fix it. Any help would be greatly appreciated.

one[i] is a single character. If you want to copy FROM position i, then you should use

Code:

strcat(str, &one[i]);

--
Mats

Ah, of course! That's fixed it, thank you much.