If, else
If bla bla bla, then(else) bla bla bla
Just like English~
General Comments
In each of the following forms, the statement can be either a
simple statement or a compound statement. A true expression
means one with a nonzero value.
Form 1
if (expression)
statement
The statement is executed if the expression is true.
Form 2
if (expression)
statement1
else
statement2
If the expression is true, statement1 is executed. Otherwise,
statement2 is executed.
Form 3
if (expression1)
statement1
else if (expression2)
statement2
else
statement3
If expression1 is true, statement1 is executed. If expression1 is
false but expression2 is true, statement2 is executed. Otherwise,
if both expressions are false, statement3 is executed.
Example
if (legs == 4)
printf("It might be a horse.\n");
else if (legs > 4)
printf("It is not a horse.\n");
else /* case of legs < 4 */
{
legs++;
printf("Now it has one more leg.\n");
}