CS 101 Problem Solving and Structured Programming in C Sami Rollins Spring 2003

Introduction What is computer programming? What is this class about? Who should take this class?

Administrative Information Class web page

Assignments Reading – Chapter 1 Homework 0 – due Monday

Computer Hardware Main memory Secondary memory CPU Input devices Output devices

Computer Software Operating system –Examples? Applications –Examples? How is a new application developed?

Computer Programs At the lowest level – machine instructions – One step up – assembly language –ADD A More user friendly – high level languages –C = A + B; –Examples?

Translation High level language must be translated into a language the computer can understand High-level Code Compiler Machine Instructions

Writing Programs Understand requirements Write an algorithm Implement your algorithm Test your code

What is an algorithm? A specific set of instructions An algorithm to make a PBJ sandwich?

Hello World /* * Name: Sami Rollins * Source file name: hello.c * My first "hello, world" program in C. */ #include //the main function int main (void) { //print the phrase printf("Hello, world!"); return(0); }

Errors You WILL have errors in your programs Syntax Errors –Compiler doesn’t understand code –Ex. – printf(Hello, world!”); –Sometimes error messages don’t match problem Logic –Program runs, but doesn’t do what you want –Ex. – printf(“Hell, world!”); –Can be hard to track down