Variables in C Programming Language
Notes:
Variables in C Programming Language
Variable:
Variable is a named memory location, whose value can change during the execution of a program.
Constant:
Constant is a named memory location, whose value never changes during the execution of a program.
i.e. constants stay constant whereas variables vary.
Declaring and initializing variables in C:
W.K.T. In order to store and process different types of data & data values computer uses its memory (RAM). To allocate a chunk of memory and access it within a program, we need to declare a variable or a constant. Declaring a variable or a constant: means allocating a memory location for some data
In order to change the value in a variable or constant, we need to initialize or assign a value to it.
Initializing a variable or a constant: means assigning the initial value to that allocated memory location
Syntax for declaring and initializing variables:
// declaration of a single variable
datatype nameOfVariable;
Ex:
int playerScore;
Note: By default the value of a variable is garbage value
// initialization of a single variable
nameOfVariable = value;
Ex:
playerScore = 0;
// declaration and initialization of a single variable
datatype nameOfVariable = value;
Ex:
int playerScore = 0;
// declaration of multiple variables
datatype nameOfVariable1, nameOfVariable2,...;
Ex:
int playerScore, playerHealth;
// initialization of a single variable
nameOfVariable1 = value;
nameOfVariable2 = value;
Ex:
playerScore = 0;
playerHealth = 100;
// declaration and initialization of multiple variables
datatype nameOfVariable1 = value, nameOfVariable2 = value,…;
Ex:
int playerScore=0, playerHealth=100;
Example code:
#include <stdio.h>
int main()
{
/*
int playerScore;
printf("player score= %d\n",playerScore); // 2
playerScore = 0;
printf("player score= %d\n",playerScore); // 0
int playerScore = 0;
printf("player score= %d\n",playerScore); // 0
int playerScore, playerHealth;
printf("player score= %d\n",playerScore); // 2
printf("player health= %d\n",playerHealth); // 80
playerScore =0;
playerHealth=100;
printf("player score= %d\n",playerScore); // 0
printf("player health= %d\n",playerHealth); // 100
int playerScore=0, playerHealth=100;
printf("player score= %d\n",playerScore); // 0
printf("player health= %d\n",playerHealth); // 100
*/
int playerScore = 0;
printf("player score= %d\n",playerScore); // 0
playerScore = 10;
printf("player score= %d\n",playerScore); // 10
return 0;
}
