C无限读入

可以用EOF来检查，EOF = -1

int input;
while(scanf("%d",&input) != EOF)
{
        //......
}

C++无限读入

int input;
while(cin >> input)
{
        //......
}

整行 :

string str;
while(getline(cin, str))
{
        // ...
}

Java无限读入

Scanner scanner = new Scanner(System.in);
while(scanner.hasNext())
{
         //...
}