You must email the TA in charge of your assigned lab and the TA for the lab to which you are going.
A virtual machine is simply a computer that is running on top of another computer emulation system. The computer emulation underneath can be an operating system like Ubuntu that has an application like VmWare workstation to emulate the VM.
You can also have what is called a bare-metal VM where you install a minimum set of instructions needed to get the VM up and running. The second option has the added benefit that you can spawn multiple VMs on the same physical device with low operating system overhead.
ssh **NETID**@fa19-cs241-**xxx**.cs.illinois.edu
where xxx is the VM number assigned to you.
We will only help you with your assignments on your VM. All other platforms are unsupported. You have been warned.
You are going to need to be on the campus network for this to work. If you want to make it work at home, make sure to log in to the campus VPN first before ssh’ing. See the development guide for details.
If you added in the past 24 hours, you should be getting an email soon about accessing your VM. If you cannot find the assignments, they are available in the release folder:
https://github-dev.cs.illinois.edu/cs241-fa19/_release/
SSH is short for secure shell (secure sh). SSH is a network protocol that leverages public key cryptography in order to connect to another computer. In the basic version, two key pairs are generated for communication. In the more advanced cases, the keys are only used for another key exchange.
All of you have probably heard of sudo before. It is short for super-user do. This lets you execute any command as root. You have that ability on your VM. Be careful. There is no way to faster crash your VM that throwing sudo around.
git is a version control system. That means it keeps track of changes in code, allows you to group changes into a commit, and provides tools to manipulate commits.
int a = 0;
size_t a_size = sizeof(a++);
printf("size: %zu, a: %d\n", a_size, a);
#define swap(a, b) temp = a; \
a = b; \
b = temp;
void selection_sort(int* a, size_t len){
size_t temp = len - 1;
for(size_t i = 0; i < temp; ++i){
size_t min_index = i;
for(size_t j = i+1; j < len; ++i){
if(a[j] < a[i]) min_index = j;
}
if(i != min_index)
swap(a[i], a[min_index]);
}
}
short mystery_bits(short input){
short max_set = ~0;
short masked = input & (0xFF00 ^ max_set);
short shifted = masked << 8;
short ret = (shifted | 0xCC);
return ret;
}
void positive_under_ten(int input){
if(0 < input < 10){
printf("Input is in the range\n");
}else{
printf("Input is not in the range\n");
}
}
int print_error(int err_num){
switch(err_num){
case ENOENT:
printf("No such file or entry\n");
case EINTR:
printf("Interrupted\n");
default:
break;
}
}
Given a program test arg1 arg2.
valgrind --leak-check=type command
type = <no|summary|yes|full>
valgrind --show-leak-kinds=all ...
layout src gives you a text-based GUIbreak <file:line|function> [if condition]: You can make powerful breakpoints by giving a line, but only under certain circumstances.watch (type *)0xADDRESS: Watches an address for a read or write and tells you when it has changed – useful for when you don’t know where the bug is.backtrace, bt to see what functions you are inup, down goes up and down a stack frameprint prints a variable (aliased p). You can use p/x to print in hex.next executes the line and goes to the next line, runs functions without stopping.finish finishes the function and breaks.step executes the line and goes to the next line. If there is a function, gdb steps into the function.