One of the simplest ways to control program flow is by using if
selection statements. Whether a block of code is to be executed or not to be executed can be decided by this statement.
The syntax for if
selection statement in C could be as follows:
if(cond)
{
statement(s); /*to be executed, on condition being true*/
}
For example,
if (a > 1) {
puts("a is larger than 1");
}
Where a > 1
is a condition that has to evaluate to true
in order to execute the statements inside the if
block. In this example "a is larger than 1" is only printed if a > 1
is true.
if
selection statements can omit the wrapping braces {
and }
if there is only one statement within the block. The above example can be rewritten to
if (a > 1)
puts("a is larger than 1");
However for executing multiple statements within block the braces have to used.
The condition for if
can include multiple expressions. if
will only perform the action if the end result of expression is true.
For example
if ((a > 1) && (b > 1)) {
puts("a is larger than 1");
a++;
}
will only execute the printf
and a++
if both a
and b
are greater than 1
.