ballerina programming language

Learn from examples

Updated for Balerina version 1.0.3
    
1. Program to output a string, integer,  and floating point

  exbl1.bal source code

# exbl1.bal  example  print string, integer, float

// exbl1.bal   example print string, integer, float, boolean  
// ballerina run exbl1.bal

import ballerina/io;

public function main (string... args) {
  io:println("exbl1.bal running");

  string hi = "Welcome to the Ballerina language";
  io:println(hi);

  int n = 3;
  io:println("n=",n);

  float x = 1.0;
  float y = 1.0e+100; // no double
  io:println("x=",x,", y=",y);

  boolean bt = true;
  boolean bf = false;
  io:println("bt=",bt,", bf=",bf);
  
  
  io:println("exbl1.bal ends");
} // end exbl1.bal



  Output from execution:

exbl1.bal running
Welcome to the Ballerina language
n=3
x=1.0, y=1.0E100
bt=true, bf=false
exbl1.bal ends



2. commands to execute the source code
   at a minimum, Windows, Linux, MacOSX.

   Windows: 
     ballerina run exbl1.bal     
  
   Linux:
     ballerina run exbl1.bal

   MacOSX
     ballerina run exbl1.bal

  Sample Makefile:
  


3. You must be able to declare variables and arrays
   and matrix of various types.

  exbl3.bal source code

// exbl3.bal   example  declare and print variable, vector, matrix  
// ballerina run exbl3.bal

import ballerina/io;

public function main (string... args) {
  io:println("exbl3.bal running");

  int n = 3;
  n = n + 3;
  io:println("n=",n);

  float x = 1.0;
  float y = x+2.0;
  io:println("x=",x,", y=",y);

  // This creates an `int` array of length 0.
  int[] a = [];
  io:println("lengthof a = ",a.length());

  // This assigns an array literal.
  int[] b = [1, 2, 3, 4, 5, 6, 7, 8];
  io:println("b[0]) = ",b[0]);
  io:println("b[7]) = ",b[7]);
  io:println("lengthof b = ",b.length());
  foreach int i in 0...7 { io:println("b[",i,"]=",b[i]); }

  // Arrays are unbounded in length.
  // They can grow up to any length based on the given index.
  // In this example, the length of the array is 1000.
  b[999] = 23;
  io:println("b[999] = ",b[999]);
  io:println("lengthof b = ",b.length());

  //This initializes an array of int arrays.
  int[][] iarray = [[1, 2, 3, 4], [10, 20, 30, 40], [5, 6, 7,8]];
  io:println("lengthof iarray =",iarray.length());
  io:println("lengthof iarray[0] = ",iarray[0].length());

  // This initializes the outermost array with the implicit default value.
  iarray = [];
  int[] d = [9];
  iarray[0] = d;
  io:println("lengthof iarray =",iarray.length());
  io:println("lengthof iarray[0] = ",iarray[0].length());

  // This prints the first value of the two-dimensional array.
  io:println("iarray[0][0] = ",iarray[0][0]);

  // This creates a sealed `int` array of length 5.
  int[5] e = [1, 2, 3, 4, 5];
  io:println("lengthof e = ",e.length());

  // This creates a sealed `int` array of length 5
  int[5] f = [0, 0, 0, 0, 0];
  io:println("lengthof f =",f.length());

  // To infer the size of the sealed array from the array literal,
  // following syntax is used.
  int[!...] g = [1, 2, 3, 4];
  io:println("lengthof g =",g.length());
  io:println("arrays.bal finished");
  
  io:println("exbl3.bal ends");
} // end exbl3.bal

Execution output:

exbl3.bal running
n=6
x=1.0, y=3.0
lengthof a = 0
b[0]) = 1
b[7]) = 8
lengthof b = 8
b[0]=1
b[1]=2
b[2]=3
b[3]=4
b[4]=5
b[5]=6
b[6]=7
b[7]=8
b[999] = 23
lengthof b = 1000
lengthof iarray =3
lengthof iarray[0] = 4
lengthof iarray =1
lengthof iarray[0] = 1
iarray[0][0] = 9
lengthof e = 5
lengthof f =5
lengthof g =4
arrays.bal finished
exbl3.bal ends


4. You need to be able to have loops, iteration statements

  exbl4.bal source code

// exbl4.bal   example  loop, iteration  
// ballerina run exbl4.bal

import ballerina/io;

public function main (string... args) {
  io:println("exbl4.bal running");

  int i;
  int n = 3;

  io:println("n=",n,++"[",i,"]=",a[i]);
  }
} // end procedure prt_vec

function prt_mat(string name, float[][] a)
{
  foreach int i in 0..7lt;a.length()
  {
    foreach int j in 0..<a[0].length()
    {
      io:println(name+"[",i,"][",j,"]=",a[i][j]);
    }
  }
} // end procedure prt_mat

public function main (string... args) {
  io:println("exbl6.bal running");

  int k;
  int n = 2;
  io:println("n= ",n);
  int m = 3;
  io:println("m= ",m);
  
  k = add(n,m);
  io:println("k=add(n,m) ",k);

  float[] v1 = [1.0, 3.0, 5.0, 7.0];
  prt_vec("v1", v1);

  float[][] m1 = [[1.0, 2.0, 3.0], [4.0, 5.0, 6.0]];
  prt_mat("m1", m1);
  
  io:println("exbl6.bal ends");
} // end exbl6.bal


Execution output:

exbl6.bal running
n= 2
m= 3
k=add(n,m) 5
v1[0]=1.0
v1[1]=3.0
v1[2]=5.0
v1[3]=7.0
m1[0][0]=1.0
m1[0][1]=2.0
m1[0][2]=3.0
m1[1][0]=4.0
m1[1][1]=5.0
m1[1][2]=6.0
exbl6.bal ends
  

7. You need to be able to read and write files in various formats.

  exbl7.bal source code

// exbl7.bal   example    
// ballerina run exbl7.bal

import ballerina/io;

public function main (string... args) {
  io:println("exbl7.bal running");


  io:println("exbl7.bal ends");
} // end exbl7.bal


Execution output:

exbl7.bal running
exbl7.bal ends



8. You need to be able to use a number of files combined to
   build a program. This may include packages, libraries,
   operating system commands, header files, etc.

  exbl8.bal source code

// exbl8.bal   example    
// ballerina run exbl8.bal

import ballerina/io;

public function main (string... args) {
  io:println("exbl8.bal running");


  io:println("exbl8.bal ends");
} // end exbl8.bal


Execution output:

Last updated 11/13/2019