Array is a variable which stores different values of the same data type. It is useful to organize multiple variables. To declare an array DIM (dimension) statement is used. Lets take an example to declare an array.
DIM numbers(10)
Here DIM is a keyword to declare array, similarly ‘numbers’ is a name of array. If you want to create a string array variable then you need to add dollar ($) at the end of the name of array variable. 10 inside the parentheses means this array can hold 11 elements, yes 11 elements there is a first index array 0 also (0 to 10), but it can store only number value because ‘numbers’ is a numerical variable. Lets see simple example of array in QBASIC.
Example 1:
CLS DIM num(5) num(0) = 2 num(1) = 4 num(2) = 5 num(3) = 10 num(4) = 6 num(5) = 9 PRINT num(0); num(1); num(2); num(3); num(4); num(5) PRINT num(3) + num(5) END
Output:
2 4 5 10 6 9 19
Example 2:
We can take data in array from the user by using looping statement. Following program will take 5 numbers from the users and print the sum of numbers.
CLS DIM num(4) sum = 0 PRINT "Enter any 5 numbers" FOR i = 0 TO 4 INPUT " :: "; num(i) sum = sum + num(i) NEXT i PRINT "The Sum = "; sum END
Video Tutorials for more info
WE can also create an array of string variables.
Example 3:
CLS DIM name$(3) name$(0) = "Ramesh" name$(1) = "Ram" name$(2) = "Bimal" name$(3) = "Sunil" PRINT name$(0), name$(3) END
Output:
Ramesh Sunil
Example 4:
Following program gets the name and marks of 5 students and print them with result, by assume pass mark = 32.
CLS DIM name$(1 TO 5) DIM marks%(1 TO 5) FOR i = 1 TO 5 PRINT i INPUT "Enter Name : "; name$(i) INPUT "Enter Marks : "; marks%(i) NEXT i PRINT "Name", "Marks", "Result" FOR j = 1 TO 5 IF marks%(j) >= 32 THEN r$ = "Pass" ELSE r$ = "Fail" END IF PRINT name$(j), marks%(j), r$ NEXT j END
In the above program two array variables are created first one is ‘name$’ which is string array variable and second one is ‘marks%’ numeric array variable. In the first Looping statement it will take name and marks of 5 students, and in the second loop it compare the marks with 32, if the marks is greater then or equal to 32 then it will store “Pass” value in variable r$, otherwise it will store “Fail” in variable r$ and it displays name, marks and result on the screen. Both loop will be repeat 5 times.
Variable Types
The non-string variables we’ve used in the above program are actually called single precision variable, which is the method of variable declaration. This type of variables are used to store number that can contain a decimal value (such as 1.89, 3.1415 etc). So, they are also known as ‘floating point’ variable.
Other types of variables used in QBSIC are given below.
INTEGER : A non floating point variable (no decimal point value) that can store integers between -32768 to 32,767.
LONG : Same as INTEGER, but it contain numbers between -2,147483,684 to 2,147,483,647.
DOUBLE : Same as SINGLE but it can store twice a many digits.
Using special characters
We can use special characters to declare different types of variables. Which are given below.
! | Single precision |
# | Double precision |
% | Integer |
& | Long |
$ | String |
We can add above special characters at the end of the variable name to declare different variables as our required.
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