CPSC 355: Tutorial 1

Introduction

J. J. Horacsek

PhD Student

Fall 2017

Introduction

Joshua Horacsek (PhD Student)

joshua.horacsek@ucalgary.ca

MS 625A

http://cpsc.ucalgary.ca/~joshua.horacsek/

Policy:

  • No food or drink
  • Be academically honest
  • Be respectful of your peers

Connecting the Arm Server

For Linux/macOS users:

ssh arm.cpsc.uclagary.ca -lyour.username

For Windows users:

https://www.ucalgary.ca/cpsc/tech/services/computing_resources

Use PuTTY: https://www.ucalgary.ca/cpsc/tech/services/putty_usage

Some Simple Bash

When you log into the ARM server, you'll be presented with a bash (Bourne Again SHell) command prompt. Initially you're in your home directory. Some simple commands are:

  • pwd - prints the current working directory
  • ls - shows the contents of the current directory
  • mkdir - create a new directory
  • cd - change directory
  • rm - remove file

Bash is actually a scripting language, but you'll only need to know basic commands to get by in this course. See this for more info on bash.

Editing Files

Easy mode:

nano filename.c

Productivity mode:

Nano is a barebones text editor, it's great for quick and easy file editing, and has an easier learning curve comapared to emacs.

vim filename.c

Vi (improved) is a text editor that very heavily relies on text commands. It's a bit of an effort to learn, but improves workflow once you've memorized the key commands.

Vim

By default Vim is in command mode:

  • i - changes to insert mode
  • w - moves the cursor to the next word
  • b - moves the cursor to the previous word
  • u - undo
  • :w - write the file
  • :q - quit
  • ZZ save and quit

Cheat sheet: https://vim.rtorr.com/

When you're in insert mode, type as normal, then esc puts you back in command mode

Hello World

#include <stdio.h>

int main(int argc, char *argv[]) 
{
    printf("Hello World!\n");

    return 0;
}
#include <stdio.h> // Include functions from the standard I/O library

// Define the main function
int main(int argc, char *argv[]) // argc: number of arguments passed
                                 // argv: array to (pointer to) argument text
{
    printf("Hello World!\n");    // prints hello world

    return 0;                    // returns 0 (error code 0 = no error)
}

To compile, type the following at the bash command prompt:

gcc filename.c -o output_name

I/O Example

#include <stdio.h>

int main(int argc, char *argv[])
{
    char name[256];
    int age;

    printf("Please enter your name:\n");
    scanf("%s", name); 

    printf("Please enter your age: \n");
    scanf("%d", &age); // & is the "address of" operator

    printf("Hello %s, you are %d years younger than I am\n", name, 27 - age);
}

Fix when age < 0, fix when age > 27.

Next time

  • Some more functions getchar(), putchar()
  • More on c strings (and format strings)
  • Pointers, addresses and arrays

CPSC 355: Tutorial 1

By Joshua Horacsek

CPSC 355: Tutorial 1

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