1. Computer Languages Humans Computers How can humans “talk to”
Humans
Computers
How can humans “talk to”
(instruct) computers?
Answer: Computer languages (e.g., Java, C,
Python, FORTRAN, Basic, C++, Lisp, Ruby, …)

2. Computer Languages Natural languages are often ambiguous.
Consider: “Alice and Betty had on the same dress.”
Alice
Betty
Alice & Betty
YES NO

3. Computer Languages
Consider: “Alice and Betty ran from the same building.”
Alice
Betty
Alice
Betty NO
YES

4. Computer Languages Natural languages contain a great deal of redundant
information, making them quite “fault tolerant.”
It deosn't mttaer in waht oredr the ltteers in a
word are, the iprmoatnt tihng is taht the frist
and lsat ltteer are in the rghit pcale.
Easy for a human to make sense of this despite
13 of the 27 words being misspelled.

5. Computer Languages
Computers typically can’t tolerate ambiguity or mistakes.
Statements (instructions) must be unambiguous and without mistakes.
Computer languages provide framework for humans to communicate to computers in a way that is almost natural to humans.

6. Computer Languages Executable Compiler File Source File
Compiler
int main() {
printf(”Hi\n”);
return 0; }
Source File
Two-step process to
execute source code.
Executable
File
Processor
Output/Results

7. Computer Languages Source File Source code is Interpreter
executed directly.
Interpreter
print(”Hi”)
Output/Results
Interactive
Environment
We will use Python interpreter.
Compilers better at catching errors and producing faster code.
Interpreters better for developing code and learning to use a language.