Declaration ➡️

To create or declare a variable in C, you do

type var_name;

where,

type is the type keyword of the variable.

var_name is the name of the variable.

Here’s a table below of the different data types in C again but with their keyword types. Note that strings are not shown here because they are declared in a different way.

Name	Type Keyword	Description	Examples
Integer	int	Represents an integer.	0, -10, 2, 150, -349
Float	float	Represents a decimal number, with at most 7-8 decimal places.	0, -10.43, 2.23420, 150.493, -349, -4230.340
Character	char	Represents a single symbol.	‘a’, ‘D’, ‘1’, ‘#’, ‘^’, ‘%’, ‘&’

Ex.

int number;
float decimal_number;

The name of the variable can only contain letters (A-Z), numbers (0-9), and underscores (_). The name must also begin with a letter. It cannot have any spaces.

Good

int valid_name;
char ValidName;
float valid_name_0439;

Bad

int 92invalid_name;
char _invalid_name;
float invalid#_name&;

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Tasks 🎯

Fix the following variable names so the program compiles:

#include <stdio.h>

int main() {
    int cool name;
    char _some_name;
    float ben&jerry;
}

Solution ✅

There may be mutliple valid solutions. Here’s one solution:

#include <stdio.h>

int main() {
    int cool_name;
    char some_name;
    float ben_and_jerry;
}