What Are C Variables?

#include <stdio.h>
int main() {
    int num = 42;
    printf("The value of num is: %d\n", num);
    return 0;
}

The value of num is: 42

#include <stdio.h>
int main() {
    int age = 25;
    float height = 1.75;
    char grade = 'A';
    printf("Age: %d, Height: %.2f, Grade: %c\n", age, height, grade);

    return 0;
}

Age: 25, Height: 1.75, Grade: A

Change Variable Values

To change the values of variables in C, you can simply assign new values to them using the assignment operator (=). 

For Example: 

#include <stdio.h>
int main() {
    int num = 5;  // Declare and initialize num with the value 5
    printf("Initial value of num: %d\n", num);
    num = 10;  // Change the value of num to 10
    printf("Updated value of num: %d\n", num);
    return 0;
}

In this example, the variable num is initially assigned the value 5. Then, the value of num is changed to 10 using the assignment statement num = 10; Finally, the updated value of num is printed using printf.

When assigning a new value to a variable, you don’t need to redeclare the variable; you can simply assign a new value to it using the assignment operator (=).

Note: If you assign a new value to an existing variable, it will overwrite the previous value:

Also: you can assign the value of one variable to another variable in C. This is known as a variable assignment or variable copying. 

For Example: 

#include <stdio.h>
int main() {
    int num1 = 5;  // Declare and initialize num1 with the value 5
    int num2;     // Declare num2
    num2 = num1;  // Assign the value of num1 to num2
    printf("num1: %d\n", num1);
    printf("num2: %d\n", num2);
    return 0;
}

In this example, the value of num1 is assigned to num2 using the assignment statement num2 = num1;. After the assignment, both num1 and num2 will have the same value of 5.

Assigning the value of one variable to another is a common operation in C and is useful for various scenarios, such as storing a calculated result in a different variable or passing the value of one variable to a function using another variable.

Add Variables Together

To add variables together in C, you can use the addition operator (+). 

For Example: 

#include <stdio.h>
int main() {
    int num1 = 5;
    int num2 = 3;
    int sum;
    sum = num1 + num2;
    printf("The sum of %d and %d is %d\n", num1, num2, sum);
    return 0;
}

In this example, num1 and num2 are two variables containing integer values. The addition operation num1 + num2 adds the values of num1 and num2 together, and the result is stored in the variable sum using the assignment operator (=).

After performing the addition, the value of the sum will be 8. The printf function is then used to display the result.

You can add variables of various data types together using the appropriate operator. For example, if you have two floating-point variables, you can use the addition operator (+) to add them together in a similar manner:

For Example: 

float num1 = 3.14;
float num2 = 2.71;
float sum;
sum = num1 + num2;
printf("The sum of %.2f and %.2f is %.2f\n", num1, num2, sum);

In this case, the result will be a floating-point sum with two decimal places.

Declare Multiple Variables

In C, you can declare multiple variables of the same type in a single declaration statement by separating them with commas. Here’s an example:

For Example: 

#include <stdio.h>
int main() {
int num1 = 5, num2 = 10, num3 = 15;
float float1 = 2.5, float2 = 3.7, float3 = 5.6;
printf("%d\n", num1+num2+num3);
printf("%.2f", float1+float2+float3);
return 0;
}

Output

30
11.80

You can also assign the same value to multiple variables of the same type:

For Example: 

#include <stdio.h>
int main() {
int num1, num2, num3;
num1 = num2 = num3 = 50;
printf("%d", num1 + num2 + num2);
return 0;
}

Output

150

C Variable Names

In C, variables are identified by unique names called identifiers. Identifiers are used to name variables, functions, and other entities in your code. It is indeed recommended to use descriptive names for your identifiers to create more understandable and maintainable code.

Using meaningful and descriptive names for your identifiers helps to improve code readability, making it easier for you and other developers to understand the purpose and functionality of variables and functions. Descriptive names can convey the intent and purpose of the identifier, making the code self-explanatory.

Here are some examples of using descriptive names for variables:

int studentAge = 25; 
float studentFee = 75.25;
char employeeName[50] = "Ajay"; 
int numberOfStudents = 80; 
double averageTemperature = 30.00;

In the examples above, the variable names are descriptive and provide information about the data they represent. This makes it easier for someone reading the code to understand the purpose and meaning of each variable.

By using descriptive names for your identifiers, you make your code more maintainable, as it becomes easier to understand and modify when needed. It is a good practice to choose meaningful and descriptive names that reflect the purpose and context of the entities they represent in your code.