---
# System prepended metadata

title: 'Some Rules to keep in mind while writing code:'

---

# Some Rules to keep in mind while writing code:

### Syntax 1: Statements should end with a semicolon ;
Code : 

```java 
1. System.out.print(100)
```
Output :
```java        
Error: ';' expected
        System.out.print(100)
                             ^
1 error
```
Explanation :
```
Line 1 gives error because ; is missing.
```

### Syntax 2: Java is case sensitive which  can differentiate between lower and upper case.
Code : 
``` java 
1. system.out.print(5000);
```
Output : 
```java 
Error: package system does not exist
		system.out.print(5000);
		      ^
1 error
``` 
Explanation : 
```plaintext 
Line 1 gives error because S in System should be uppercase.
```

### Syntax 3: In order to print text we use double quotes.
Code1 :
```java
1. System.out.print(Rahul);
```

Output :

```java
Error: cannot find symbol

        System.out.print(Rahul);
                         ^

symbol:   variable Rahul
```

Explanation :
```
Code will give error because " " are missing.
```

Code2 :
```java
1. System.out.print(“Rahul);
```

Output :

```java
Error: unclosed string literal

        System.out.print("Rahul);
                               ^
```

Explanation :
```
This will give error because opening quote is present before Rahul but closing quote (") is missing after Rahul.
```



### Syntax 4: () , {}, “ ” → These should be in pairs 
Code1 :
```java
1. System.out.print("Rahul"};
```

Output :
```java
Error: ')' expected

        System.out.print("Rahul"};
                                ^
1 error
```

Explanation :
```
This will give an error because we have to use same type of brackets on both sides.
```

Code2 :
```java
1. System.out.print(Rahul;
```

Output :
```java
Error: ')' expected

        System.out.print(Rahul;
                              ^
1 error
```

Explanation :
```
This will give an error because we use brackets in pairs.
```


### Syntax 5: Comments
Compiler will ignore the statements which are written as comments 

1. **Single Line comment**

   > // Single Line Comment

    Code1 : 
    ```java 
    1. // System.out.println(“Super”); 
    2. System.out.println(“Excited”);
    ```
    Output:
    ```java 
    Excited
    ```
    Explanation :
    ```plaintext 
    Line 1 statement is a comment. So, Super is not getting printed.
    ```

2.  **Multi Line comment**
    >/*
    This is a
    multi - line
    comment
    */

    Code2 :
    ```java 

    1. System.out.println("Good Morning");
    2. /* System.out.println(“Super”); 
    3. System.out.println(“Excited”);
    4. */
    5. System.out.println("Hello");
    ```
    Output:
    ```java 
    Good Morning
    Hello
    ```

    Explanation :
    ```
    Line 2, 3 and 4 are a part of multi line comment. So, Super and Excited are not getting printed in the output.
    ```
### Syntax 6: print() vs println()



Code1 :

```java
1. System.out.print(“Hello Guys!!”);
2. System.out.print(“My name is Rahul.”);
```

Output :
```java
Hello Guys!!My name is Rahul.
```


Code2 :
```java
1. System.out.println(“Hello Guys!!”);
2. System.out.print(“My name is Rahul.”);
```

Output :
```java
Hello Guys!!
My name is Rahul.
```

Explanation :
```
> System.out.print → Prints the output and cursor remains in same line.
> System.out.println → Prints the output and cursor goes to the next line.
```


