Basic Concepts

This page will explain you basic concepts of C programming language. Following C language basic concepts are discussed through various programs given on this page: 

data types, declaring variables, assigning values to variables, processing values of variables, displaying content to console and reading user input.

In C language any user defined name is called identifier. This name may be variable name, function name, goto label name, any other data type name like structure, union, enum names or typedef name. We need to follow some rules while declaring variables (identifiers) in C program. To know more about variable declaration rules click here.

We will learn use of various fundamental concepts using following C programs.

Sample Programs

//To read roll number and marks from user and display it on screen.
//This program shows how to declare and use int variables.

void main()
 int marks,rollno;

 printf("Enter your Roll No:");
 scanf("%d", &rollno);

 printf("Enter your Marks:");
 scanf("%d", &marks);
 printf("Your Roll No: %d. \n", rollno);
 printf("Your marks: %d", marks);
/* Output
Enter your Roll No:101
Enter your Marks:70
Your Roll No: 101.
Your marks: 70

//Simple Calculator using C. Addition, Subtraction, Multiplication, and Division.
void main()
   int number1, number2;

   printf("Enter number1:");

   printf("Enter number2:");

   printf("Addition of two numbers: %d\n", number1 + number2 );
   printf("Substraction of two numbers: %d\n", number1 - number2 );
   printf("Multiplication of two numbers: %d\n", number1 * number2 );
   printf("Division of two numbers: %d\n", number1 / number2 );
/* Output
Enter number1:10
Enter number2:5
Addition of two numbers: 15
Substraction of two numbers: 5
Multiplication of two numbers: 50
Division of two numbers: 2

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