How to Write a Command Line Program in C?
In C, we can provide arguments to a program while running it from the command line interface. These arguments are called command-line arguments. In this article, we will learn how to write a command line program in C.
How to Write a Command Line Program in C?
Command line arguments are passed to the main() function. For that purpose, the main function should have the following signature:
int main( int argc , char *argv[] ){ // Write your code }
Here, argc is the number of arguments, and argv[] is the argument in the form of an array of strings.
Note: The argv[0] always contains the source file name.
C Program to Pass Command Line Arguments
C
// Program to demonstrate Command line arguments in C #include <stdio.h> #include <stdlib.h> int main( int argc, char * argv[]) { // code to calculate the sum of n numbers passed to CLA int i, sum = 0; // iterating the loop till the the number of // command-line arguments passed to the program // starting from index 1 for (i = 1; i < argc; i++) { sum = sum + atoi (argv[i]); } printf ( "Sum of %d numbers is : %d\n" , argc - 1, sum); return 0; } |
Command Line Instruction
// assume that the file name is solution ./solution 10 20 30 40 50
Output
SUM of 5 numbers is: 150
Note: The command line arguments are separated by space so if you want to pass a space-separated string as a command line argument, then enclose them inside the “”.
To know more, refer to the article – Command Line Arguments in C