Term
What happens here?
char str1[] = "Hello\0everyone!";
char str2[] = "Happy Friday!";
printf(str1); |
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Definition
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Term
What is wrong with this code? (4)
char str1[] = "Hello\0everyone!";
printf(%s, str1[6]; |
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Definition
1. %s wants a pointer to a character, but str1[6] gives it an integer
2. (characters are upgraded to integers!). 3. To get a character pointer, we need to do &str1[6].
4. Or str1 + 6. |
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Term
| Difference between sizeof and strlen |
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Definition
| Sizeof gets the size in memory, which includes \0. Strlen does not include \0. |
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Term
| Difference between char str[] = "Hello World!" and char *str = "Hello World!" |
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Definition
| The first is mutable, the second is an immutable string literal |
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Term
| What is the difference between strcmp and strncmp? Strcopy and strncopy? |
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Definition
| Strncmp and strncopy specify a fixed length |
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Term
What is wrong with this code?
char str1[] = "Hello World!";
char str2[] = str1; |
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Definition
| str2[] is initialized as a constant pointer. That means it can't point at anything else. |
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Term
What is wrong with this code?
char str1[] = "Hello World!";
char str2[12];
strcpy(str2, str1); |
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Definition
| Char str2[12] specifies the length of the array, not the size. Str1 has a size of 13 because of the null character, so when it gets copied until str2, the null character is not copied. That means the null character is placed outside the bounds of str2. |
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Term
Why doesn't this code work?
char *amazing_str = "Gotta get down on Friday!";
strcpy(amazing_str, "Matthew"); |
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Definition
| Amazing_str has been declared as an immutable string literal |
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Term
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Definition
| You can put in a string with size less than int, but not greater than int |
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Term
When to use:
char *my_string
char other_str []
char amazing_str[128] |
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Definition
| Use * when you don't need to change anything. Use [] when you might want to change the characters in place, but don't anticipate having to put new things in. Use [128] (or some other large number) when you anticipate having to add new things in. |
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Term
| Difference between strcpy and strcat |
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Definition
| Strcpy overrides what is in the destination string, strcat just attaches to the end of it |
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Term
| Program to get age input from the user |
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Definition
printf("Please enter your age: ");
int age;
scanf("%d", &age); |
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Term
What does this mean?
ls -l / > list_of_files.txt |
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Definition
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Term
| Why is stderr slower than stdout? |
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Definition
| Stderr is not buffered, it is flushed to the terminal immediately |
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Term
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Definition
| Output redirection -- sends stdout to a file instead of the terminal |
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Term
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Definition
| Output redirection, but appending to the file instead of overwriting |
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Term
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Definition
| Input redirection, reads from file instead of stdin |
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Term
| Why can printing to the terminal be misleading sometimes? |
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Definition
| There is no guarantee that what you did in your code will match what's displayed on the screen because standard input is getting buffered. Printf() might execute, but the program might crash before any output is displayed. |
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Term
| How does buffered I/O speed up the I/O process? |
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Definition
| It collects multiple I/O operations, combines them, and then executes them as one big operation |
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Term
| Tradeoff between flushing every output versus using buffering |
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Definition
Flushing: sometimes when printing, your program crashes before the butter gets cleared, and data is lost
Buffering increases speed. Performing printf takes several steps: get permission from OS, OS goes to device, device gets your display involved |
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