Loops are among the most basic and powerful programming
concepts. A loop in a computer program is an instruction that repeats until a
specified condition is reached. In a loop structure, the loop asks a question.
If the answer requires action, it is executed. The same question is asked again
and again until no further action is required. Each time the question is asked
is called an iteration. A computer programmer who needs to use the same
lines of code many times in a program can use a loop to save time.
Just about every programming language includes the concept of a loop.
High-level programs accommodate several types of loops. C, C++,
and C# are all high-level computer programs and can use various kinds
of loops
Types of Loops
A for loop is a loop that runs for a preset number of times.
A while loop is a loop that is repeated as long as an expression is
true. An expression is a statement that has a value.
A do while loop or repeat until loop repeats until an
expression becomes false.
An infinite or endless loop is a loop that repeats
indefinitely because it has no terminating condition, the exit condition is
never met or the loop is instructed to start over from the beginning. Although
it is possible for a programmer to intentionally use an infinite loop, they are
often mistakes made by new programmers.
A nested loop appears inside any other for, while, or do
while loop.
A goto statement can create a loop by jumping backward to a label. However,
this is generally discouraged as a bad programming practice. Some complex code
allows a jump to a common exit point that simplifies the code.
Loop Control Statements
A statement that alters the execution of a loop from its designated sequence is
a loop control statement. C#, for example, provides two loop control
statements.
A break statement inside a loop terminates the loop immediately.
A continue statement jumps to the next loop iteration, skipping any
code in between.
Basic Structures of Computer Programming
Loop, selection, and sequence are the three basic structures of computer
programming. These three logic structures are combined to form algorithms for
solving any logic problem. This process is called structured programming.
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