Difference Between InputStream And InputStreamReader

I read that InputStream is used for byte based reading it reads 1 byte at a time.And InputStreamReader is used for charcter based reading so it reads one charcter at a time so no need to convert this first to int then read it.Here is reading using InputStream.

input=new FileInputStream("D:/input.txt");
int c;
while((c=input.read())!=-1)
{
System.out.print((char)c);
}

and here is reading using InputStreamReader

input=new FileInputStream("D:/input.txt");
reader=new InputStreamReader(input,"UTF-8");
int c;

while((c=reader.read())!=-1)
{
System.out.print((char)c);
}

so what is difference between InputStream and InputStreamReader in both case i have to use a Int and then read it and at the end if I want to print that data I have to cast that with "(char)c".So what is advantage of using InputStreamReader?