Basic about C language

Question

Q. Variables and rules of variables declaration.
Q. Write Simple C Program to add two number using constant and variables.
Q. Write Simple C Program to add two number taking input from user.

Answer 1

Is this your homework? What do you expect from this thread?

If you need help, link your code attempt and describe the issue.

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NO.

Answer 2

Sure, let's cover some basics and provide examples for your questions:

### 1. Variables and Rules of Variable Declaration in C:

In C, variables are used to store data. Here are some rules for declaring variables:

- Variable names must begin with a letter or underscore.
- Following characters can be letters, digits, or underscores.
- Variable names are case-sensitive.
- Keywords cannot be used as variable names.
- White spaces are not allowed in variable names.

### 2. Simple C Program to Add Two Numbers using Constants and Variables:

```c
#include <stdio.h>

int main() {
// Variables declaration
int num1, num2, sum;

// Assign values
num1 = 10;
num2 = 20;

// Addition
sum = num1 + num2;

// Print the result
printf("Sum: %d\n", sum);

return 0;
}
```

### 3. Simple C Program to Add Two Numbers Taking Input from the User:

```c
#include <stdio.h>

int main() {
// Variables declaration
int num1, num2, sum;

// Input from user
printf("Enter first number:

Answer 3

Please check the first few lessons of the Sololearn C course, you will find your answers.
https://www.sololearn.com/learn/courses/c-introduction