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Ringkasan c++
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THE if STATEMENT
Its syntax is :
if (condition) statement;
+++ condition is an integral expression.+++ statement is any executable statement.+++ The statement will be executed if the value of integral expression is nonzero.
Example :
int main () {int n, d;cout << “Enter two positive integers: “;cin >> n >> d;if (n%d)
cout << n << “ is not divisible by “ << d << endl;}
Enter two positive integers: 66 7
66 is not divisible by 7
66 % 7 is 3. Since integral value is not zero, the expression is interpreted as a true condition.
Enter two positive integers: 66 7
56 % 7 is 0, which interpreted to mean false, so divisibility message is not printed.
In C++, whenever an integral expression is used as a condition, the value 0 means “false” and all other value mean “true.”
THE if...else STATEMENT
Its syntax is:
if (condition) statement1;
else statement2;
+++ condition is an integral expression.+++ statement1 and statement2 are executable expression.+++ If the value of the condition is nonzero then statement1 will execute ;
otherwise statement2 will execute +++ Note that the if..else is only one statement, even though it requires two semicolons.
Example :
int main ()
{
int n, d;
cout << “Enter two positive integers: “ ;
cin >> n >> d;
if (n%d)
cout << n << “ is not divisible by “ << d << endl;
else
cout << n << “ is divisible by “ << d << endl;
}
Enter two positive integers: 56 7
56 is divisible by 7
56 % 7 is zero. The expression is a false condition, so the statement after the else is executed.
The if..else statement causes one of two alternative statements to execute depending upon whether the condition is true
KEYWORDS
A keyword in a programming language is a word that is already defined and is reserved for a
unique purpose in programs written in that language. Standard C++ now has 74 keywords:
Two kinds of keywords.
A reserved word is a keyword that serves as a structure marker, used to define the syntax of the language. The keywords if and else are reserved words.
A standard identifier is a keyword that names a specific element of the language. The keywords bool and int are standard identifiers because they are names of standard types in C++.