Probably just some silly error I've overlooked, but even after looking back over the code several times I don't see what's wrong.

Code:
#include <iostream>
#include <string>
using namespace std;

void letters(string test, int plus, int strsize);

int main(){

string test="A string";
int strsize=test.size();

letters(string test, int plus, int strsize);

return 0;
}

void letters(string test, int plus, int strsize){
	for(plus=0; plus<strsize; plus++){
	cout<<test[plus];
	}
}

Error:
Code:
/home/cerin/string.cpp: In function `int main()':
/home/cerin/string.cpp:12: error: parse error before `,' token