THE C PROGRAM WORKSHOP

1. THE C PROGRAM WORKSHOP

2. Workshop Features Bins for parts and supplies Door for unexpected results to go out Door for expected results to go out WORKSHOP A B C D Communication with other shops Door for requests to go in X Y Z Instructions and operating procedures Various tools

3. A computer program written in C is like a workshop Current Data (Information) main Transformed Data (Information) It brings data into the program from the outside world, performs some processing with it, makes some changes to it, and then returns it to the outside world in a different form

4. C Program Entrances and Exits Constants and variables STANDARD ERROR (stderr) main STANDARD OUT (stdout) A B C D File and Device Input/Output STANDARD IN (stdin) X Y Z Instructions and operating procedures Operations and functions

5. Data Types • Integers (int) • Numbers with decimal points (float) • Characters (char) • Words and Phrases (ex. char phrase[10]) • Tables (ex. int values[10], float matrix[20][30]) • Records (ex. struct myRecordType)

6. Data Storage Locations int aNumber; float aValue; char aSymbol; char phrase[LENGTH]; int values[15];

7. Simple Operations • Storage (=) • Addition (+) • Subtraction (-) • Multiplication (*) • Division (/) • Modulo (%) • Comparison (==, !=, <, <=, >, >=)

8. Instructions and Decisions • variableLocation = expression • Ex. count = 17 * MAX_LOOPS; • if (Boolean condition) statement else statement • Ex. if (numberIsValid) count++; else count--; • while (Boolean condition) statement • Ex. while (count > MAX_LOOPS) count = count – 5; • for (statement; condition; statement) statement • Ex. for (i = 0; i < size; i++) printf(“%d\n”, table[i]);

9. Technical Vocabulary: C Keywords auto double int struct breakelse long switch case enum register typedef char extern return union const float short unsigned continuefor signed void default goto sizeof volatile doif static while (Note: Keywords in bold-face font are used with data types)

10. Standard C Library Functions • Standard Input and Output: • printf, scanf, getchar, gets • Conversion of Data: • isalpha, isdigit, tolower, toupper • Math: • sin, cos, tan, sqrt, log, exp • Working with Files: • fopen, fclose, fscanf, fprintf, fgets

11. Example Program - C Source Code int main(void){int theCheckNbr;char theAccount;char theTaxCode;float theAmount;float theBalance;theBalance = 2391.52; printf("Ck Nbr Acct Tax Amount Balance\n");printf("------ ---- --- ------ -------\n");theCheckNbr = 234;theAccount = ‘B';theTaxCode = ‘Z';theAmount = 34.56;theBalance = theBalance - theAmount;printf("%6d %2c %2c %6.2f %7.2f\n", theCheckNbr, theAccount, theTaxCode, theAmount, theBalance);return 0;} // End main

12. Example Program Output Ck Nbr Acct Tax Amount Balance ------ ---- --- ------ ------- 234 A Z 34.56 2356.96

13. Example Program Exercise • Using the current pattern of statements in the program, add the source code to display the last two lines of the report shown below • Also, change the order of the report columns Ck Nbr Amount Acct Balance Tax ------ ------ ---- ------- --- 234 34.56 B 2356.96 Z 235 192.73 T 2164.23 W 236 75.00 G 2089.23 X 