Beginning C Programming for Engineers CSCI1190

1
Beginning C Programming for Engineers (CSCI-1190)

• Instructor Gang Chen (cheng3_at_rpi.edu)
• Office Hour Thursday 2-4pm (or by appointment)
• Office Lally 9A
• Webpage www.cs.rpi.edu/cheng3/teaching/1190

2
Basic Computer Model
CPU
Input
Output
Memory
Instructions Data
Von Neumann Architecture
3
Programming Languages
1300042774 1400593419 1200274027
Machine Languages
LOAD A ADD B STORE C
Assembly Languages
CAB
High-Level Languages
4
Creating Programs
C libaray
hello.o
compile
hello
hello.c
Link
Edit
Source File (High-Level Languages)
Object File (Machine Languages)
Executable
gcc o hello hello.c
nedit hello.c
5
Unix Commands
6
Hello, World

• / Hello, world program /
• include ltstdio.hgt
• int main()
• printf("hello, ")
• printf("world\n")
• return 0

• Editing xemacs hw.c or nedit hw.c or vi hw.c
• Compiling gcc Wall o hello hw.c
• Executing hello

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Basic Programming Concepts

• Comment To explain what the program is for and
  why it is the way it is.
• Preprocessing Done before the program is
  compiled.
• To include header files containing information
  about C libraries
• Statement A line of code that tells computer to
  perform some action. Always ended with a
  semicolon().
• Invoking functions
• Function A module often consisting of a set of
  statements.
• Two functions in the hello world program main,
  printf

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In Class Exercise 1-1

• Escape Sequences are used to control printf to do
  something other than printing characters.
• Modify the hello world program to try out various
  escape sequences like
• \n Newline. Position cursor at the beginning of
  the next line.
• \t Tab. Move cursor to the next tab stop.
• \a Alert. Sound the system bell.

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Arithmetic Operators

• To form expressions
• Many statements are merely expressions.
• Normal order of operations is followed.
  Parentheses can be used.
• If you are not sure, look up in Appendix C.
  Operator Precedence Charts, p1193

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Arithmetic Operators An Example

• / Arithmetic operators /
• include ltstdio.hgt
• int main()
• printf("73d\n",73)
• printf("7-3d\n",7-3)
• printf("73d\n",73)
• printf("7/3d\n",7/3)
• printf("73d\n",73)
• printf("7.0/3.0f\n",7.0/3.0)
• return 0

11
Variables

• Variable Name for a memory object. Variable
  names must start with letters and contain
  letters, digits, and underscores.
• a, b, i, j, counter, number_of_points, c1234,
• Type What the variable represents. Could be of
  integer, floating point number, character,
  string, and many others.
• int, float, double, char,
• Declaration Tells compiler about variables and
  their type.
• int i,j
• float sum

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Numeric Types
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Reading Inputs

• include ltstdio.hgt
• int main()
• float a,b
• printf("Please input the first
  number\n")
• scanf("f",a)
• printf("Please input the second
  number\n")
• scanf("f",b)
• printf("abf\n",ab)
• printf("a-bf\n",a-b)
• printf("abf\n",ab)
• printf("a/bf\n",a/b)

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Assignment

• / Arithmetic operators /
• include ltstdio.hgt
• int main()
• int a,c
• int b4
• a3
• cab
• printf(Sum d d -gt d\n,a,b,c)
• ab--
• prinf(Now ad and bd\n,a,b)
• return 0

15
In-Class Exercise 1-2

• Write a program to calculate the average of three
  floating point numbers, namely 2.3, 3.4, 4.5.
• Using scanf function
• Using assignment