1. EG280 Computer Science for Engineers Fundamental Concepts Chapter 1

2. Spring 2001EG280 CS for Engineers2 Computing Systems: Hardware and Software A computer is a machine designed to perform operations specified with a set of instructions called a program. Hardware refers to the computer equipment. –keyboard, mouse, terminal, hard disk, printer Software refers to the programs that describe the steps we want the computer to perform.

3. Spring 2001EG280 CS for Engineers3 Computer Hardware CPU Internal Memory External Memory InputOutput Processor ALU CPU - Central processing unit ALU - Arithmetic and logic unit ROM - Read only memory RAM - Random access memory

4. Spring 2001EG280 CS for Engineers4 Computer Software Operating System - Provides an interface with the user –unix, windows, linux,... Software Tools –word processors (MicrosoftWord, WordPerfect,...) –spreadsheet programs (Excel, Lotus1-2-3,...) – mathematical computation tools (MATLAB, MathCAD,...) Computer Languages –machine (binary) language –assembly language –high level languages (C, C++, Ada, Fortran, Basic, java)

5. Spring 2001EG280 CS for Engineers5 Executing a Computer Program C language source code Machine language (object code) Compile Linker Error Messages Other useful information Other object modules Executable Code (.exe) Other useful information

6. Spring 2001EG280 CS for Engineers6 Key Terms Source Program - printable/Readable Program file Object Program - nonprintable machine readable file Executable Program - nonprintable executable code Syntax errors - reported by the compiler Linker errors - reported by the linker Execution/Run-time errors - reported by the operating system Logic errors - not reported

7. Spring 2001EG280 CS for Engineers7 The C Programming Language General purpose, machine-independent language Developed at Bell Labs in 1972 by Dennis Ritchie American National Standards Institute(ANSI) approved ANSI C standard in 1989 Today, much C-language programming is done with C++, an object-oriented programming language

8. Spring 2001EG280 CS for Engineers8 Table 1.2 Software Life-Cycle Phases PhasePercent of Effort Definition3 Specification15 Coding and modular testing14 Integrated testing8 Maintenance60

9. Spring 2001EG280 CS for Engineers9 An Engineering Problem-Solving Methodology 1. PROBLEM STATEMENT 2. INPUT/OUTPUT DESCRIPTION 3. HAND EXAMPLE 4. ALGORITHM DEVELOPMENT 5. TESTING

10. Spring 2001EG280 CS for Engineers10 First Program – Sum of Two Numbers /******************************************************************/ /* Program chapter1 */ /* */ /* This program computes the sum two numbers */ #include int main(void) { /* Declare and initialize variables. */ double number1 = 473.91, number2 = 45.7, sum; /* Calculate sum. */ sum = number1 + number2; /* Print the sum. */ printf(“The sum is %5.2f \n”, sum); /* Exit program. */ return 0; } /***************************************************************************/