1. EECE.2160 ECE Application Programming
Instructor:
Dr. Michael Geiger
Spring 2018
Lecture 36:
Exam 3 Preview

2. ECE Application Programming: Exam 3 Preview
Lecture outline
Announcements/reminders
Late/regrade submissions: Dr. Geiger + TA
Program 7 regrades due tomorrow (5/3)
Program 8 regrades due Monday (5/7)
Program 9 due today
Program 10 (extra credit) due Wednesday, 5/9
Deals with file I/O and bitwise operators
Up to 4 points of extra credit on your final average
Only one chance to turn in—no resubmissions
Grading will be tougher than typical assignment
Exam 3: Thursday, 5/10, 6:30-9:30 PM in Ball 210
Course evaluation to be posted
Today’s class
Exam 3 outline
4/8/2019
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
Strings + all lectures after Exam 2 (lectures 22, 24-25, 27-34)
Format similar to Exams 1 & 2
Code reading, writing, and 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
4/8/2019
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 questions on
String basics
String functions
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: CR/CW questions on
fopen()/fclose()
Formatted I/O using fprintf()/fscanf()
Unformatted I/O using fread()/fwrite()
Standard I/O streams: stdin, stdout
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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: CR/MC questions on
fgetc(), getchar(), ungetc()
fgets()
Bitwise operators: CR/MC questions on
Operator basics
Set/clear/flip bits
Extracting bits
Dynamic allocation: MC questions on
Basic allocation: malloc(), calloc(), realloc(), free()
Extra credit: may cover any topic above
4/8/2019
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’
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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
strncpy() not guaranteed to add null terminator
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
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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
strncat() guaranteed to add null terminator
4/8/2019
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;
Access members using
Dot operator: student1.middle = ‘J’;
Arrow (if pointers): sPtr->GPA = 3.5;
Typically passed to functions by address
4/8/2019
ECE Application Programming: Exam 3 Preview

10. 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;
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
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ECE Application Programming: Exam 3 Preview

11. 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)
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ECE Application Programming: Exam 3 Preview

12. 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);
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ECE Application Programming: Exam 3 Preview

13. Review: bit manipulation
Bitwise operators: | & ^ ~
Used for desired logical operations
Used to set/clear bits
Bit shifts: << >>
Used to shift bits into position
Used for multiplication/division by powers of 2
Common operations
Setting/clearing/flipping individual bit
Setting/clearing/flipping multiple bits
Extracting bits
i.e. x = (x & 0x00FFFF00) >> 8;
4/8/2019
ECE Application Programming: Exam 3 Preview

14. Review: hexadecimal output
To print a number in hex, use %x or %X
%x prints characters a-f in lowercase
%X prints characters A-F in uppercase
To show leading 0x, use the # flag
To show leading 0s, use precision with total # chars
Field width + 0 flag also works unless value = 0
Examples (assume var1 = 0x1A2B)
printf(“%x”, var1)  1a2b
printf(“%X”, var1)  1A2B
printf(“%#x”, var1)  0x1a2b
printf(“%.6x”, var1)  001a2b
printf(“%#.6x”, var1)  0x001a2b
4/8/2019
ECE Application Programming: Exam 3 Preview

15. Review: dynamic memory allocation
Basic block allocation:
void *malloc(size_t size);
Allocate block and clear it:
void *calloc(size_t nmemb,
size_t size);
Resize previously allocated block:
void *realloc(void *ptr,
Deallocation function:
void free(void *ptr);
Dynamically allocated array
arr = (int *)malloc(n * sizeof(int));
Can then use array notation: arr[i] = 0;
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ECE Application Programming: Exam 3 Preview

16. ECE Application Programming: Exam 3 Preview
Next time
Exam 3 Q & A session
Reminders:
Late/regrade submissions: Dr. Geiger + TA
Program 7 regrades due tomorrow (5/3)
Program 8 regrades due Monday (5/7)
Program 9 due today
Program 10 (extra credit) due Wednesday, 5/9
Deals with file I/O and bitwise operators
Up to 4 points of extra credit on your final average
Only one chance to turn in—no resubmissions
Grading will be tougher than typical assignment
Exam 3: Thursday, 5/10, 6:30-9:30 PM in Ball 210
Course evaluation to be posted
4/8/2019
ECE Application Programming: Exam 3 Preview