Questions and Answers
What is the main difference between getchar() and getch() functions?
What is the purpose of the srand() function?
What is the return type of the strlen() function?
What is the purpose of the strcmp() function?
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How can you convert a command line argument from a string to an integer?
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Study Notes
Input Functions
-
getc()
reads a character from the standard input (usually the keyboard) and returns it as an integer. -
getchar()
is a macro that callsgetc()
withstdin
as the argument, making it equivalent togetc(stdin)
. -
getch()
is a non-standard function that reads a character from the standard input without echoing it to the console. -
getche()
is a non-standard function that reads a character from the standard input and echoes it to the console.
Random Number Generation
-
rand()
generates a random integer between 0 andRAND_MAX
(a constant defined in ``). -
srand()
seeds the random number generator with an initial value, allowingrand()
to produce a sequence of random numbers.
Character Classification
-
isupper()
returns a non-zero value if the character is an uppercase letter. -
islower()
returns a non-zero value if the character is a lowercase letter.
String Manipulation
strcpy()
- Copies the string pointed to by the second argument into the array pointed to by the first argument.
- Returns a pointer to the destination array.
- Example:
strcpy(dest, "hello");
copies the string "hello" into the arraydest
.
strcat()
- Appends the string pointed to by the second argument to the end of the string pointed to by the first argument.
- Returns a pointer to the destination array.
- Example:
strcat(dest, "world");
appends the string "world" to the end of the string indest
.
strlen()
- Returns the length of the string pointed to by the argument.
- Example:
strlen("hello");
returns 5.
strcmp()
- Compares the string pointed to by the first argument to the string pointed to by the second argument.
- Returns an integer indicating the result of the comparison: 0 if the strings are equal, less than 0 if the first string is less than the second, greater than 0 if the first string is greater than the second.
- Example:
strcmp("hello", "goodbye");
returns a value indicating that "hello" is less than "goodbye".
Command Line Argument Conversion
- To convert a command line argument from a string to an integer, use the
atoi()
function from ``. - Example:
int arg = atoi(argv[1]);
converts the first command line argument to an integer.
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Description
This quiz covers the differences and usage of various C programming functions such as getc, getchar, getch, getche, rand, srand, isupper, islower, strcpy, strcat, strlen, and strcmp. It also includes converting command line arguments to integers.