VisuAlg Variables and Data Types Explained

A variable is a named box in memory. In VisuAlg every box has a type, and the type decides what you can store in it. Getting types right early prevents most of the "type incompatible" errors new students meet.

The four primitive types

Note that decimal numbers use a dot, not a comma: write 1.75, never 1,75.

Declaring variables

var
   idade, ano: inteiro
   altura, peso: real
   nome: caractere
   matriculado: logico

You can declare several variables of the same type on one line, separated by commas. All declarations live in the var section, before inicio.

Naming rules

• Start with a letter or underscore.
• Use only letters, digits and underscores; no spaces or accents.
• Do not use reserved words such as se, para or inicio.
• VisuAlg is not case-sensitive, so Nota and nota are the same variable.

Mixing types in expressions

You can assign an inteiro to a real variable, but not the reverse. Division with / always produces a real result, so storing it in an inteiro causes an error. When you need whole-number division, use \, and use % (or mod) for the remainder.

algoritmo "divisao"
var
   a, b, q, r: inteiro
   media: real
inicio
   a <- 17
   b <- 5
   q <- a \ b      // 3
   r <- a % b      // 2
   media <- a / b  // 3.4
   escreval(q, " ", r, " ", media)
fimalgoritmo

Logical values in practice

Logical variables shine when you store the result of a comparison: aprovado <- nota >= 7. You can then test se aprovado entao later, which keeps conditions readable.

Converting between types

Built-in functions help when you need to switch types: int(x) drops the decimals of a real, numpcarac(n) turns a number into text and caracpnum(t) turns text into a number.

Now put your variables to work with conditional statements.