1. EECE.2160 ECE Application Programming
Instructors:
Dr. Lin Li & Dr. Michael Geiger
Spring 2019
Lecture 36:
Exam 3 Preview

2. ECE Application Programming: Exam 3 Preview
Lecture outline
Announcements/reminders
Program 8 due today
Program 9 (extra credit) due 5/8
Exam 3: Tue, 5/7, 3-6 PM, Ball 210
Course evals online; will also have hard copies available
You’ll submit eval at exam
Wed. 5/8: All code due by 11:59 PM
Program 9: Worth up to 4 points extra credit on final avg
Resubmission deadline for remaining programs
Today’s class: exam 3 preview
Exam outline
Review of material
9/2/2019
ECE Application Programming: Exam 3 Preview

3. ECE Application Programming: Exam 3 Preview
Exam 3 notes
Allowed one 8.5” x 11” two-sided note sheet
No other notes or electronic devices
Exam lasts 3 hours (but written for ~50 min)
Coverage
All lectures after Exam 2 (lectures 24, 26-35)
Format similar to Exams 1 & 2
Code reading, writing, multiple choice questions
One 10 point extra credit question at end
For this exam, you may attempt the extra credit question even if you haven’t attempted to solve all other problems
9/2/2019
ECE Application Programming: Exam 3 Preview

4. ECE Application Programming: Exam 3 Preview
Exam 3 outline (CR = code reading, CW = code writing, MC = multiple choice)
Strings: CR/CW questions on
String functions (copy, concatenate, length, compare)
Strings as function arguments
Structures: CR/CW questions on
Basic structure accesses
Dot operator (i.e., s1.x)
Pointer access (i.e., p->GPA)
Arrays of structures
Nested structures
File input/output: MC questions that may involve
fopen()/fclose()
Text file I/O using fprintf()/fscanf()
Binary file I/O using fread()/fwrite()
Standard I/O streams: stdin, stdout
9/2/2019
ECE Application Programming: Exam 3 Preview

5. ECE Application Programming: Exam 3 Preview
Exam 3 outline (CR = code reading, CW = code writing, MC = multiple choice)
Character/line I/O: MC questions that may involve
fgetc(), getchar(), ungetc()
fgets()
Extra credit: may focus on any topic above
Should clearly understand earlier material, too
9/2/2019
ECE Application Programming: Exam 3 Preview

6. ECE Application Programming: Exam 3 Preview
Review: strings
Represented as character arrays
Can be initialized using string constants
char hello[] = “Hello”;
Can access individual elements
hello[3] = ‘l’;
Can print directly or with formatting
Print directly: printf(hello);
Print w/formatting using %s: printf(“%s\n”, hello);
Reading strings: scanf(“%s”, str);
Reads all characters up to (but not including) first space, tab, or newline
Must leave enough room for terminating ‘\0’
9/2/2019
ECE Application Programming: Exam 3 Preview

7. Review: String functions
In <string.h> library:
Copying strings:
char *strcpy(char *dest,
const char *source);
char *strncpy(char *dest,
const char *source,
size_t num);
Return dest
Does not append ‘\0’ unless length of source < num
Comparing strings:
int strcmp(const char *s1, const char *s2);
int strncmp(const char *s1, const char *s2, size_t num);
Character-by-character comparison of character values
Returns 0 if s1 == s2, >0 if s1 > s2, <0 if s1 < s2
9/2/2019
ECE Application Programming: Exam 3 Preview

8. Review: String functions (cont.)
Find # of characters in a string
size_t strlen(const char *s1);
Returns # characters before ‘\0’
Not necessarily size of array
“Add” strings together—string concatenation
char *strcat(char *dest,
const char *source);
char *strncat(char *dest,
const char *source,
size_t num);
Returns dest
9/2/2019
ECE Application Programming: Exam 3 Preview

9. ECE Application Programming: Exam 3 Preview
Review: Structures
User-defined types; example:
typedef struct {
char first[50];
char middle;
char last[50];
unsigned int ID;
double GPA;
} StudentInfo;
Can define variables of that type
Scalar: StudentInfo student1;
Array: StudentInfo classList[10];
Pointer: StudentInfo *sPtr;
9/2/2019
ECE Application Programming: Exam 3 Preview

10. Review: structures (continued)
Initialization very similar to array initialization:
StudentInfo student1 =
{ “John”, ‘Q’, “Smith”,
, 3.75 };
Access members using
Dot operator: student1.middle = ‘J’;
Arrow (if pointers): sPtr->GPA = 3.5;
Typically passed to functions by address
9/2/2019
ECE Application Programming: Exam 3 Preview

11. Review: Arrays of structures
Initializing structure arrays:
studentInfo list[3] =
{ {"John", 'Q', "Smith", 123, 3.0},
{"Jane", 'A', "Jones", 456, 3.95},
{"Mary", 'X', "Ford", 789, 3.72} };
Access members of structs in arrays—each array element = 1 struct, so use dot operator
list[0].GPA = 2.5;
strcpy(list[1].first, "Janet");
9/2/2019
ECE Application Programming: Exam 3 Preview

12. Review: Nested structures
Structures can contain other structures:
typedef struct {
char first[50]; // First name
char middle; // Middle initial
char last[50]; // Last name
} Name;
Name sname; // Student name
unsigned int ID; // ID #
double GPA; // Grade point
} SINew;
9/2/2019
ECE Application Programming: Exam 3 Preview

13. Review: Nested structure accesses
Will need multiple dot operators to access field within nested structure
Given SINew s1;
s1.sname  Name structure within s1
s1.sname.middle  middle initial of name within s1
Structure pointer typically only to top-level structure
Given SINew *sp = &s1;
sp->sname  Name structure within s1
sp->sname.middle  middle initial of name in s1
9/2/2019
ECE Application Programming: Exam 3 Preview

14. ECE Application Programming: Exam 3 Preview
Review: File I/O
Open file: FILE *fopen(filename, file_access)
Close file: fclose(file_handle)
Formatted I/O:
fprintf(file_handle, format_specifier, 0+ variables)
fscanf(file_handle, format_specifier, 0+ variables)
Unformatted I/O:
size_t fwrite(pointer, element size, # elements, file_handle)
size_t fread(pointer, element size, # elements, file_handle)
9/2/2019
ECE Application Programming: Exam 3 Preview

15. ECE Application Programming: Exam 3 Preview
Review: Generic I/O
Special I/O streams in C
stdin: standard input
stdout: standard output
printf(“Hello\n”) ==
fprintf(stdout, “Hello\n”);
scanf(“%d”, &x) ==
fscanf(stdin, “%d”, &x);
Can write generic code that deals either with specific file or standard input/output
9/2/2019
ECE Application Programming: Exam 3 Preview

16. ECE Application Programming: Exam 3 Preview
Review: End of file
Two ways to check for end of file:
Text files: Check if fscanf() == EOF
More common: do fscanf() as part of loop condition, and continue while EOF not reached
e.g. while (fscanf(fp, “%d”, &y) != EOF)
Binary files: feof(file_handle);
Note: both functions indicate EOF after failed read operation
Must try to read data and discover that there’s nothing to read before testing for EOF
9/2/2019
ECE Application Programming: Exam 3 Preview

17. Review: character/line input
Character input
int fgetc(FILE *stream);
int getchar();
int ungetc(int c, FILE *stream);
Line input
char *fgets(char *s, int n, FILE *stream);
9/2/2019
ECE Application Programming: Exam 3 Preview

18. ECE Application Programming: Exam 3 Preview
Next time
Exam 3: Tuesday, 5/7, 3-6 PM, Ball 210
Don’t forget to complete your course eval before exam!
Hard copies available from Dr. Geiger’s office
Reminders:
Program 8 due today
Program 9 (extra credit) due 5/8
Wed. 5/8: All code due by 11:59 PM
Program 9: Worth up to 4 points extra credit on final avg
Resubmission deadline for remaining programs
9/2/2019
ECE Application Programming: Exam 3 Preview