C++ Prime Plus
Setting out to C++
- C++ standard function header:
int main()
;void mian()
- Header Filenames: C++ header files have no .h extension. For example, the C++ version of math.h is the cmath header file;
- Function form:
Functions prototypes:void simon(int)
;double taxes(double)
; Function:void simon(int n) {...}
;double taxes(double t) {...}
;
Dealing with Data
- Integer Types:
A short integer is at least 16 bits wide;
A int integer is at least as big as short;
A long integer is at least 32 bits wide and at least as big as int;
A long long integer is at least 64 bits wide and at least as big as long;
- Some integer limits
#include <iostream>
#include <climits> // use limits.h for older systems
int main()
{
using namespace std;
int n_int = INT_MAX; // initialize n_int to max int value
short n_short = SHRT_MAX; // symbols defined in climits file
long n_long = LONG_MAX;
long long n_llong = LLONG_MAX;
// sizeof operator yields size of type or of variable
cout << "int is " << sizeof(int) << " bytes." << endl;
cout << "short is " << sizeof n_short << " bytes." << endl;
cout << "long is " << sizeof n_long << " bytes." << endl;
cout << "long long is " << sizeof n_llong << " bytes." << endl;
cout << endl;
cout << "Maximum values:" << endl;
cout << "int: " << n_int << endl;
cout << "short: " << n_short << endl;
cout << "long: " << n_long << endl;
cout << "long long: " << n_llong << endl << endl;
cout << "Minimum int value = " << INT_MIN << endl;
cout << "Bits per byte = " << CHAR_BIT << endl;
cin.get();
return 0;
}
Output:
int is 4 bytes.
short is 2 bytes.
long is 4 bytes.
long long is 8 bytes.
Maximum values:
int: 2147483647
short: 32767
long: 2147483647
long long: 9223372036854775807
Minimum int value = -2147483648
Bits per byte = 8
- Initialization with C++11
int rheas = {12}; // set rheas to 12
int emus{7}; // set emus to 7`
int rocs = {}; // set rocs to 0`
int psychics{}; // set psychics to 0
- Display values in hex and octal
#include <iostream>
using namespace std;
int main()
{
using namespace std;
int chest = 42;
int waist = 42;
int inseam = 42;
cout << "Monsieur cuts a striking figure!" << endl;
cout << "chest = " << chest << " (decimal for 42)" << endl;
cout << hex; // manipulator for changing number base
cout << "waist = " << waist << " (hexadecimal for 42)" << endl;
cout << oct; // manipulator for changing number base
cout << "inseam = " << inseam << " (octal for 42)" << endl;
return 0;
}
- C++ Escape Sequence Codes
Character Name | ASCII Symbol | C++ Code |
---|---|---|
Newline | NL | \n |
Horizontal tab | HT | \t |
Vertical tab | VT | \v |
Backspace | BS | \b |
Carriage return | CR | \r |
Alert | BEL | \a |
Backslash | \ | \\ |
Question mark | ? | \? |
Single quote | ' | \' |
Double quote | '' | \'' |
- The const Qualifier
The general form for creating a constant is this:const type name = value
;
If your background is in C,you might feel that the #define statement,which is discussed earlier,already does the job adequately. But const is better. For one thing, it lets you specify the type explicitly. Second, you can use C++’s scoping rules to limit the definition to particular functions or files. Third, you can use const with more elaborate types, such as arrays and structures.
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