Parse all characters in char*

#include <iostream>

using namespace std;

void myfunc(char* char_in)
{
    bool empty = true;
    for(int i = 0; char_in[i]; ++i) 
    {
        if(char_in[i] != ' ' && char_in[i] != '\t' && char_in[i] != '\r' && char_in[i] != '\n') 
        {
            printf("Char* is not empty. Found a non space character @ %d\n\n", i);
            empty = false;
            break;
        }
    }
    if(empty)
    {
        printf("Char* is empty\n\n");
    }
}


int main()
{
    char* char_i = "    Hello   ";
    myfunc(char_i);
    
    system("PAUSE");
    return 0;
}