Wouldn’t it be great to open up Nautlius (equivalent to Windows-Explorer in Ubuntu) and be able to open up your terminal in that specific folder by simply right clicking and choosing an Open in Terminal option? Unfortunately this option isn’t set by default. Luckily there are two ways to install this option.
Command Line Arguments allow the user to run the program thruogh the terminal as well as pass in arguments into your program in one line. Most common use of command line arguments, are to pass in “strings” that represent file names from which you are going to read data from.
This is how you would write a simple program without command line arguments.
double square(int number) {
return number*number; }
int main() {
int number;
cin >> number;
cout << square(number) << endl;
return 0;
}
To run this program you’d do the following in the terminal. ($ denotes your input)
This is how you would use command line arguments.
double square(int number) {
return number*number; }
int main(int argc, char* argv[]) {
int number = atoi(argv[1]); //Convert our c-string to int using the atoi function
cout << square(number) << endl;
return 0;
}
To run this, you’d simply do the following in the terminal.
The int argc parameter denotes the number of arguments passed in.
The char* argv[] parameter denotes a char pointer to a c-string.
So, typing the following:
Would produce the following:
In other words, the arguments are passed in as c-strings reason for why we converted our c-string to an int using the atoi function.
You may pass in any type of arguments. Try the following challenges to learn more.
Challenge 1: Create a program using command line arguments where you pass in your name, and two numbers, adds the numbers together and displays them both in the terminal.
Challenge 2: Create a program that accepts one int and returns the square of the number as shown above. The difference is that you need to error check your program. In other words, if they don’t pass in an int value or more than one int value, you should terminate the program. Hint: Use argc, and if statements.
Need more help? Go ask in the forums where our committed community will surely answer all your questions!
If you are new to Linux and it’s terminal, you might be wondering how to move around? I’ll show you how with some basic terminal commands.
Below I’ll list a few examples with comments denoted by // Read more »
Here is a step by step detailed guide on showing you how to write and compile a C++ program in Linux. For demonstration purposes, I’ll show you how to write and compile Hello World!
Difficult: Relatively Easy
1. First, let’s locate and open up our handy terminal.
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