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Line Labels:
Line labels are much like pascal's except that they do not
need to be defined, however they cannot be numbers.
EXAMPLE
char where;
void main()
{
start:
cout << 'This is the beginning of the program\n';
cout << 'Would you like to go to the start again? '
cin >> where;
if ((where == 'Y')||(where == 'y'))
goto start;
}
Command: (void)
in C++ commands/procedures (user defined commands) have two
parts to it. the prototype, and the actual coding.
The prototype is a way of defining the command for the program
much like you define variables.
void do_nothing(); //defining the prototype.
void main()
{
do_nothing(); // command call.
}
void do_nothing() //actual command coding.
{
cout << "Inside do_nothing";
}
Functions:
functions in C+ are much like pascal where you must define
the type of return value of the function. You must also
define a prototype for functions as you have to for
commands.
There are two ways of doing functions as well, if a function
is simply returning a mathematical operation you can
use an inline function which is simply the prototype and
actual coding in one, up at the top.
EXAMPLE
//normal functions.
int add(int, int); //defining function with two integers passed
//to it, for use inside function.
int a,b,answer;
void main()
{
a = 7; b = 3;
answer = add(a,b);
}
int add(int a, int b)
{
return a+b;
}
//inline functions
int a,b,answer;
inline int add(int a, int b)
{ return a+b; }
void main()
{
a = 7; b = 3;
answer = add(a,b);
}
Control Structures:
Like Pascal, C++ has similar control structures, but
lacks the file scanning structure that TAS has. In
C++ they must also be blocked off with {} if you wish to
have more than one line executed within the control
structures.
EXAMPLE
while ( a < b )
{
cout << a << "\n"
a++; // same as a = a + 1;
}
do {
cout << b << "\n";
b++;
} while (b < a);
for(int x;x <= 20; x++) //x++ is the same as x = x + 1
{
cout << x << "\n";
} //note: only one line was in this for-loop so it
// would be ok to leave off the braces. {}
//in switch statements, on each different case you need
// to include the work 'break' at the end of each one
// to prevent it from executing all the cases.
int num;
cout << "Please enter a number under 10. "
cin >> num;
switch (num)
{
case 1: case 2: case 3:
cout << "under 4";break;
case 4: case 5: case 6:
cout << "under 6 over 3";break;
case 7: case 8: case 9:
cout << "under 10 over 6";break;
default:
//default is the same as an 'else'
//or an 'otherwise' in tas.
cout << "You did not enter a number
inside the desired range.";
}
if (a > b)
cout << "a is greater than b";
else if (a < b)
{
cout << "b is greater than a\n";
cout << "Two lines withing a if-then needs braces.";
}
else
cout << "They are equal";
INPUTTING VALUES:
In C++, it's much like Pascal, in that you cannot control
your input without significant coding and label/udc
(user-defined commands) to do the same that TAS can do in
one line. You also cannot use the arrow keys to move from
each input value, like you can in TAS.
EXAMPLE
int x;
void main() {
cout << "Please enter a number. ";
cin >> x;
}
Outputs:
In C++ the output is simple, but hard to position.
EXAMPLE
cout << "This is a test"; //This leaves cursor at the end
//of the output.
cout << "This is a test\n"; //returns cursor to next line.