写出下面程序的运行结果。
public class TestOne {
public static void main(String[] args) {
int a = 10;
int b = 20;
int c = a + b;
System.out.println("a + b = " + c); //a + b = 30
System.out.println(a + " + " + b + " = " + a + b);
System.out.println(a + " + " + b + " = " + (a + b));
String name = "jack";
System.out.println("登录成功,欢迎" + name + "回来!");
}
}