"ISO" error on compiler ???

Hey guys, im having this problem with my compiler or my code, i dont know which one. everytime i tell it to compile this code, it gives the error "ISO", and i have no idea what that means. here is the code. it happens on lines 15, 19, 23, and all the other if and else if and else lines. whats the problem?

#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;

int Aa = 0, Ee = 0, Ii = 0, Oo = 0, Uu = 0;
int counter;
string str;

int Vowelcount (int Aa,int Ee,int Ii,int Oo,int Uu,string str,int counter)
{
for (counter = 0; (counter - 1) > str.length(); counter++)
{
if (str[counter] == "a")
{
Aa = Aa + 1;
}
else if (str [counter] == "e")
{
Ee = Ee + 1;
}
else if (str [counter] == "i")
{
Ii = Ii + 1;
}
else if (str [counter] == "o")
{
Oo = Oo + 1;
}
else if (str [counter] == "u")
{
Uu = Uu + 1;
}
}
cout << Aa << "\t" << Ee << "\t" << Ii "\t"
<< Oo << "\t" << Uu << endl;
return 0;
}
int main ()
{
cout << "enter a string" << endl;
cin >> str;
counter = 0;
Vowelcount(Aa, Ee, Ii, Oo, Uu, str, counter);
system{"PAUSE");
return 0;
}

The "ISO" is not the important part of the error, look at the rest. Anyways, str[counter] is a single char and you compare it to "a", which is actually a string. You meant to compare it to 'a', a character.

hey ubergeek thanks for the help i got it to take away the ISO error, by the way that was all that was shown, but now when im in runtime, it returns 0 for the variable Aa. whats happening now?

I'm not quite sure, my psychic powers are off today. What is the updated code? And what did you give it as input?

hey thanks again ubergeek heres the code

#include <cstdlib>
using namespace std;

int Aa = 0, Ee = 0, Ii = 0, Oo = 0, Uu = 0;
int I;
string str;

int Vowelcount (int Aa,int Ee,int Ii,int Oo,int Uu,string str,int I)
{
for (I=0;I>str.length();I++)
{
if (str [I] == 'a')
{
Aa = Aa + 1;
}
else if (str [I] == 'e')
{
Ee = Ee + 1;
}
else if (str [I] == 'i')
{
Ii = Ii + 1;
}
else if (str [I] == 'o')
{
Oo = Oo + 1;
}
else if (str [I] == 'u')
{
Uu = Uu + 1;
}
}
return Aa;
}
int main ()
{
cout << "enter a string" << endl;
cin >> str;
Vowelcount(Aa, Ee, Ii, Oo, Uu, str, I);
cout << Aa;
string red;
cin >> red;
return 0;
}

Your organization doesn't make much sense to me. You have Aa and the rest as global variables (so all functions can access them), but then you pass them to Vowelcount() anyways. Then Vowelcount returns a value, but you ignore it and output the global variable instead (this is why you see 0 output--the global variable was copied when you passed it to Vowelcount and never modified). Review global variables and function parameters/return values.

hey thankyou so much ubergeek that was mighty bitchin in the kitchen.