Syntax Comparison of Golang with C and Java - Mindbowser

Syntax Comparison of Golang with C and Java - Mindbowser

• 2.
  Syntax C Java Go Extension.c .java .go VM Needed Not needed JVM is there to convert java files to class files Not needed Compiler TurboC javac gc Program Execution Starts from main() function Starts from public static void main(String[ ] args) starts from func main() and should be in package main
• 3.
  Syntax C Java Go Variable Declaration inta; float b; int a,b,c; Initialization int a=25; char c=’a’; int a; float b; a int var c string var a,b,c float Initialization var o,p int=34,65 k=45.67 (type of variable auto judged by compiler) Shorthand notation a:=30 (only inside function) Data Types bytes,short,int,long, double,float,char,void Primitive bytes,short,int,long ,double,float, boolean,char uint, int,float32,..., complex, byte,rune
• 4.
  C Java Go Constantconst int LEN=10 final int PI=3.14 const LEN int=10 Operators All operators like Arithmetic,Logical, Bitwise etc. are same All operators like Arithmetic,Logical, Bitwise etc. are same All operators like Arithmetic,Logical, Bitwise etc. are same Decision Making Statements (If else) if(i>5){ flag=true } else{ flag=false } if(i>5){ flag=true } else{ flag=false } if i>5{ flag=true }else{ flag=false } Syntax
• 5.
  C Java Go SwitchCase switch(i){ case 1: …… break; . . default:..... break ; } switch(i){ case 1: …… break; . . default:..... break ; } Expression switch switch marks{ case 90: grade==’A’ case 50,60,70:grade==’C . default: fmt.Println(“Invalid”) } Type switch var x interface{} switch x.(type){ case int: fmt.Println(“x is int”) default: fmt.Println(“I don’t know”) } Syntax
• 6.
  C Java Go Forloop for(i=1;i<5;i++){ ……... } for(i=1;i<5;i++){ ………….. } for i:=0;i<5;i++{ ……….. } for key,val:=range numbers{ ………….. } While Loop while(i<10){ i++; } while(i<10){ i++; } for sum<100{ sum+=sum } Syntax
• 7.
  C Java Go FunctionDeclaration int sum(int,int) int sum(int x,int y){ …………… return } Calling int add; add=sum(10,20) -Supports pass by value and reference Define method public int sum(int a,int b){ ………….. return } -Only pass by value func sum(no int) (int){ …… return .. } -Both pass by value and reference Function Overloading No Yes No Syntax
• 8.
  C Java Go VariadicFunctions No printMax(10,20,30) public static void printMax(double… numbers){ ……... } func sum(num ...int) int{ ….. …. } Ex. Println() is implemented in “fmt” package func Println(a ...interface{})(n int,err error) String char greet[6]={ ‘h’,’e’,’l’,’l’,’o’,’0’ } String s=new String(“Hello”) var greeting=”Hello” Syntax
• 9.
  C Java Go StringFunctions strcpy(str1, str2) strcat(str1,str2) strlen(s1)............ str.length() str.concat(str2) str.compareTo(str2 ) String is made up of runes. Rune is UTF Format (A- ’65’,a-’97’) len(str) strings.join(str1,str 2) Arrays Fixed size data structure Declaration int array[10]; Accessing Elements int value=array[10] Declaration int[ ] numbers Creation numbers=new int[10] Declaration var number [10]int Initialization Var bal=[10] int{...............} Syntax
• 10.
  C Java Go SliceThere is no growable data structure java.util.Collection package provides dynamic growable array. E.g List,Set,Map etc Growable data structure Declaration var numbers []int Creation numbers=make([ ]int,5,5) 5 len, 5 is capacity append(),copy() Default value - nil Map There is no map data structure in C Key, Value pair Map m=new HashMap() Map[key] value Default value is nil Syntax
• 11.
  C Java Go Map- m.put(“Zero”,1) put( ) get( ) ForEach to iterate over collection and array var dictionary=map [string] int dictionary[“Zero”]=1 Create using make var dict=make(map [string] int) Range -> to iterate over slice,map for key,val:=range values { ……... } Syntax
• 12.
  C Java Go Struct/ Class Collection of fields and methods struct book{ int id; char name[50]; char author[50]; }book; //Access members struct book book1; strcpy(book1.id,400) Java does not have struct but have class class Books{ int id; String name; String author; void display(){ …………... } } Books b=new Book(); b.name=”Vision” Go have struct to hold data in variables. type struct Book{ id int; name string; } func(book3 *Book) display() { ………….. } book1:=new(Book) var book2 Book; book2.name=”Go” Syntax
• 13.
  C Java Go EmbeddingIt is like inheritance in Java class A { …. } Class B extends A { ... } type Person struct{ Name string } func (per *Person) speak(){ …….. } type Mobile struct{ Person Model String } Mob:=new(Mobile) mob.Person.speak( ) Syntax
• 14.
  C Java Go PointerDirect address of memory location int *a a=&b; NULL pointer Always assign null value to pointer variable when you don’t know exact address to assign int *a=NULL; Java does not support pointer var a *int var fp *float32 a=&p NIL pointer var *p int=nil Syntax
• 15.
  C Java Go InterfaceC does not have interface concept -Collection of only abstract methods (from java 8 it supports static methods also) -Classes implements interface public interface Animal{ public void eat(); public void sleep(); } public class Monkey extends Animal{ ……….. } -Provides method signatures type Shape interface { area() float64 } type square struct{ side float64 } func(sq Square)area( ) float64 { return sq.side*sq.side } Same method signature is implemented Syntax
• 16.
  C Java Go Gohas empty interface which is like object class in java. An empty interface can hold any type of value. fmt.Println(a ...interface{ }) Type Casting Convert variable from one to another data type (type) expression int sum=5,count=2; Double d=(double) sum/count Widening byte->short->int->float-> long->double float=10 Narrowing double->float->long->int- >short->byte int a=(float)10.40 var i int=10 var f float64=6.44 fmt.Println(float64(i)) fmt.Println(int(f)) Syntax
• 17.
  C Java Go ErrorHandling -No direct support for error handling But it returns error no. perror() and strerror() used to display text message associated with error no int dividend=20; int divisor=0; int quotient; if(divisor==0){ fprintf(stderr,”Divide by zero”); exit(-1); } Exception Handling -Exception is problem arises during program execution. Checked/Unchecked Ex. try{ …… } catch(Exception ex){ …….. } finally{ …….. } No try/catch mechanism. Instead it is having defer,panic,recover concepts. -Provides error interface type error interface{ Error() string } Normally function returns error as last return value. Use errors.New() for specifying error msg. Syntax
• 18.
  C Java Go Concurrency/ Multithreading Doesn’t have support. Java have multithreading concept for simultaneous execution of different tasks at same time. We need to extends Thread class or Runnable interface and then implement run( ) and write your code start(),run(),join(),sleep(),... Here, we use goroutines for concurrent execution. To make function as goroutine just append go in front of your function. Two goroutines are communicating using channel concept Syntax
• 19.
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