Functions and More
Homework 1
• Due September 11 @ 11:59pm
• return a string
• count characters in a string
• call functions in a function
git
• Version control
• Might cover this in more detail later in the
semester
• For now
– git clone
https://hartloff@bitbucket.org/hartloff/cse250fall2015.git
• If SSH keys are needed (timberlake)
– upload private key
– git clone git@bitbucket.org:hartloff/cse250fall2015.git
clone alternative
• Download files from the BitBucket web
interface
– Might get you through this course
– Not ideal
• If you want to write software, you will need to
learn version control at some point
ftp (file transfer protocol)
• To move files across machines
• If you want to develop locally
– Use this to move your files to timberlake
– submit_cse250 hw1.cpp
• Need ftp software
– FileZilla
– sftp://timberlake.cse.buffalo.edu
– Port 22
On to C++
Functions in C++
• Function declaration
– float foo(int);
– C++ functions must be declared before they are called
• Function definition
– float foo(int i){return i*1.5;}
– can be defined later
• Put all declarations at the beginning of your file
• Header file
– Go one step further and put declarations in a separate
file
– #include “stringFunctions.h”
Makefile
• Useful when a project contains multiple files
• A way to compile all necessary files with one
command
– make
• Blank space matters in Makefiles
• All Makefiles will be provided for you in this
class
References &
• An alias (nickname) to a variable
– int k = 3;
– int& p = k;
– p = 6;
• After executing these 3 lines
– k == 6
– Both k and p refer to the same location in memory
• Why not assign 6 to k directly?
– When you have access to p, but not k
back to functions
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•
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void square(int i){i = i*i;}
int r = 5;
square(r);
r == 5
When square is called
• int i = r;
• i = i*i;
back to functions &
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•
•
•
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void square(int& i){i = i*i;}
int r = 5;
square(r);
r == 25
When square is called
• int& i = r;
• i = i*i;
• Use references when a function should alter a
parameter
•
Caution: Be aware if a function takes a reference or not