• Skip to main content
  • Skip to primary sidebar
  • Skip to secondary sidebar
  • Skip to footer

Computer Notes

Library
    • Computer Fundamental
    • Computer Memory
    • DBMS Tutorial
    • Operating System
    • Computer Networking
    • C Programming
    • C++ Programming
    • Java Programming
    • C# Programming
    • SQL Tutorial
    • Management Tutorial
    • Computer Graphics
    • Compiler Design
    • Style Sheet
    • JavaScript Tutorial
    • Html Tutorial
    • Wordpress Tutorial
    • Python Tutorial
    • PHP Tutorial
    • JSP Tutorial
    • AngularJS Tutorial
    • Data Structures
    • E Commerce Tutorial
    • Visual Basic
    • Structs2 Tutorial
    • Digital Electronics
    • Internet Terms
    • Servlet Tutorial
    • Software Engineering
    • Interviews Questions
    • Basic Terms
    • Troubleshooting
Menu

Header Right

Home » C » Pointer » Command Line Arguments in C
Next →
← Prev

Command Line Arguments in C

By Dinesh Thakur

In C, we can supply arguments to ‘main’ function. Every C program has at least one function main(). The programs that we have discussed so far don’t pass any arguments to the main(). A question that immediately comes to one mind is that, can we pass any argument(s) to main()?
Yes, it is possible to pass arguments to main() on many systems like DOS and UNIX from the operating system’s prompt. These arguments passed to the main () by the user at the command prompt are known as command-line arguments. Command-line arguments are parameters to main when the program starts. These arguments are supplied at the time of invoking the program.

An expanded version of main() that receives command-line arguments specified by the user at the command prompt is of the form,

main(int argc, char *argv[]) { }

Here argc and argv are the two built-in formal arguments in main() that can receive command-line arguments. The first argument, argc (argument counter), specifies the number of arguments passed in the command line. It always has a count of at least one. The second argument, argv (argument vector), is an array of char type pointers. There is always at least one char pointer in the array pointed to by argv, i.e., argv [0]. The argv [0] points to the name of the program’s executable file. Each element in the array of pointer points to the command-line argument that is treated as a string. If argc is greater than 1, then the argv parameters, argv [1], argv[2], and so on point to the command line arguments as they were entered on the command line, and argv [argc] is a NULL pointer. White spaces separate these arguments.

Now let us suppose the fruit.c program is compiled and linked. So an executable file fruit.exe will exist. If you run the executable file of the program (fruit.exe) file from the DOS prompt as follows

C:\TC> fruit.exe first.txt second.txt

Then value received by argc will be 3 (two arguments plus one program name).
The argv[0] points to the “fruit.exe”, argv[1] to “first.txt” and argv[2] points to “second.txt” and argv[3] is a null pointer.

So argv[0] = fruit.exe
   argv[1] = first.txt
   argv[2] = second.txt
   argv[3] = NULL pointer

The primary use of the command line argument is while implementing DOS commands type, copy, etc. There is no need to recompile the program every time we want to use this utility.

How to Run a Program using Command Line Arguments

Following are the steps to execute a program containing command-line arguments.

1. After typing the program, we compile the program using ALT+ F9 keys from the keyboard.
2. Then we link the program by moving to Compile > Link and then press Enter from the keyboard. As a result, an executable file is created.
3. Quit the editor by going into the File menu bar and selecting Quit or going to the OS Shell option of the File menu bar and pressing Enter. Now type the following at the prompt.

4. C:\TC>ABC data1 data2

5. When you are done, type exit at the prompt to return to the program. Now let us consider a program to show how command-line arguments work.

Program to print strings entered as command line arguments.

#include<stdio.h>
int main(int argc, char *argv[]) {
 int n;
 printf("Following are the arguments entered in the command line");
 for (n = 0; n < argc; n++) {
  printf("\n %s", argv[n]);
}
 printf("\n Number of arguments entered are\n %d\n", argc);
 return 0;
}

Explanation: After typing the program, we compile the program using Alt + F9 keys from the keyboard. Then we link the program by moving to Compile> Link and then press Enter from the keyboard. As a result, an executable file will be created. Suppose the program name is fruit.C, then its executable file would be fruit.exe.Now go to file> DOS shell and press the Enter key from the keyboard. As a result, the DOS prompt will appear on the screen.

Now type

C:\ TC>fruit apple mango

Output:

Following are the arguments entered in the command line

C:\fruit.exe
apple
mango

Number of arguments entered are 3

After this, type exit at the prompt to return to the program.

Note: We can implement various DOS internal commands like COPY, TYPE using the concept of command-line parameters.

You’ll also like:

  1. Command Line Arguments
  2. Command Line Arguments in Java
  3. Command Line Arguments in Python
  4. What is command line interface?
  5. How to run the applet from command line?
Next →
← Prev
Like/Subscribe us for latest updates     

About Dinesh Thakur
Dinesh ThakurDinesh Thakur holds an B.C.A, MCDBA, MCSD certifications. Dinesh authors the hugely popular Computer Notes blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps.

Dinesh Thakur is a Freelance Writer who helps different clients from all over the globe. Dinesh has written over 500+ blogs, 30+ eBooks, and 10000+ Posts for all types of clients.


For any type of query or something that you think is missing, please feel free to Contact us.


Primary Sidebar

C Programming

C Programming Tutorials

  • C - History
  • C - Anatomy
  • C - Constants
  • C - Identifiers
  • C - Data Types
  • C - Libraries File
  • C - Header Files
  • C - Basic Language
  • C - Data Types Sizes
  • C - Header Files Importance
  • C - Escape Sequences
  • C - Main() Purpose
  • C - Program Procedure
  • C - Control Statements
  • C - Enumeration Constant
  • C - Add numbers
  • C - Return Statement
  • C - Avoid Goto
  • C - Command Line Arguments
  • C - Switch Case
  • C - Switch Case Limitations
  • C - getchar() and putchar()
  • C - Iteration Statements
  • C - Pass by Value and Reference
  • C - Structures and Unions
  • C - Structure
  • C - Dynamic Memory
  • C - Fgets and Fputs Functions
  • C - Gets() and Puts() Functions
  • C - Armstrong Number
  • C - Storage Classes
  • C - Fibonacci Series
  • C - Precision Setting
  • C - const Parameters

C - Variable & It's Type

  • C - Variables
  • C - Variable Lifetime
  • C - Static Variable
  • C - Register Variable
  • C - Global Variables
  • C - Auto Variables
  • C - Local Variables

C - Operator & Expressions

  • C - Operator
  • C - Boolean Operators
  • C - Bitwise Operator
  • C - Arithmetic Operators
  • C - Modulus Operator
  • C - Ternary Operator
  • C - Expressions
  • C - Arithmetic Expressions

C - Array

  • C - Arrays
  • C - Array Types
  • C - Array Characteristics
  • C - Static Arrays
  • C - Global Arrays
  • C - 3D Arrays
  • C - Dynamic Arrays
  • C - Pointer to 3D Arrays
  • C - Array Elements Hold
  • C - Arrays as Function Parameters
  • C - Accessing Matrix Elements
  • C - File Handling
  • C - Matrix Multiplication
  • C - Dynamic Memory Allocation

C - Searching & Sorting

  • C - Data Structures
  • C - Linear Search
  • C - Bubble Sort
  • C - Merge Sort
  • C - Linked List
  • C - Insertion Sort
  • C - Binary Search
  • C - Selection Sort
  • C - Quick Sort

C - Functions

  • C - Functions
  • C - Functions Advantages
  • C - Void Functions
  • C - Function Call
  • C - Default Return Value
  • C - String functions

C - Pointer

  • C - Pointers
  • C - Type Casting Of Pointers
  • C - Pointer Advantages
  • C - Pointers Initialization
  • C - Vectors and Pointers

C - Differences

  • C - C Vs C++
  • C - Formal Args. Vs Actual Args.
  • C - Keywords Vs Identifiers
  • C - Strings Vs Character Arrays
  • C - Address Vs Dereference Operator
  • C - Goto Vs longjmp
  • C - Declaring Vs Defining Variable
  • C - String Vs Array
  • C - Call by Value Vs Reference
  • C - Structure Vs Union
  • C - For Vs While loops
  • C - Compiler Vs Interpreter

C - Programs

  • C Program Standard Deviation
  • C Program Calculate Tax
  • C Program Sum Series
  • C Program Merge Arrays
  • C Program Euclid’s Algorithm
  • C Program Print Weekdays
  • C Program Sum of Digits
  • C Program Print a list
  • C Program Print Pythagorean
  • C Program Quiz program
  • C Program Display Table
  • C Program Print Comma-Separated
  • C Program Prints Prime Numbers
  • C Program for Print Integer
  • C Program Count Number
  • C Program Print Color Name
  • C Program Print Odd Numbers
  • C Program Calculate area
  • C Program for a Menu
  • C Program Add Two Vectors
  • C Program Array Addresses
  • C Program Division by Zero Error
  • C Program Compare two Dates
  • C Program Tower of Hanoi
  • C Program return 3 Numbers
  • C Program for Prime Numbers
  • C Program for Factorial
  • C Program for Palindrome

Other Links

  • C Programming - PDF Version

Footer

Basic Course

  • Computer Fundamental
  • Computer Networking
  • Operating System
  • Database System
  • Computer Graphics
  • Management System
  • Software Engineering
  • Digital Electronics
  • Electronic Commerce
  • Compiler Design
  • Troubleshooting

Programming

  • Java Programming
  • Structured Query (SQL)
  • C Programming
  • C++ Programming
  • Visual Basic
  • Data Structures
  • Struts 2
  • Java Servlet
  • C# Programming
  • Basic Terms
  • Interviews

World Wide Web

  • Internet
  • Java Script
  • HTML Language
  • Cascading Style Sheet
  • Java Server Pages
  • Wordpress
  • PHP
  • Python Tutorial
  • AngularJS
  • Troubleshooting

 About Us |  Contact Us |  FAQ

Dinesh Thakur is a Technology Columinist and founder of Computer Notes.

Copyright © 2025. All Rights Reserved.

APPLY FOR ONLINE JOB IN BIGGEST CRYPTO COMPANIES
APPLY NOW