Loops are among the most basic and powerful of 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.
Nothing in the C standards prevents the case labels from being buried inside other compound statements. One rather hideous application of this fact is Duff's device. There are three kinds of loops in C. A while loop tests if a condition is true, and if so, executes its body. It then tests the condition is true.
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 have the capacity to use several types of loops.
In this tutorial, we will learn the use of while and do.while loops in C programming with the help of some examples. In computer programming, loops are used to repeat a block of code. For example, let's say we want to show a message 100 times. Then instead of. Looping is one of the key concepts on any programming language. A block of looping statements in C are executed for number of times until the condition becomes false. Loops are of 2 types: entry-controlled and exit-controlled. 'C' programming provides us 1) while 2) do-while and 3) for loop. The loops are needed to execute a block of code many of the times. In this, basically the statements are executed sequentially which means the first statement in a function is executed first than the second statement and so on. The loops are used to execute a single statement or the group of statements multiple times. Some of the loops in C are. The third part of the loop is labeled 'incrementation', because it usually takes the form of 'i' or something similar. However it can be any legal C/C statement, such as 'N += 3' or 'counter = base + delta'. In the example above, the variable i is declared before the loop, and continues to exist after the loop has completed.
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, although this is generally discouraged as a bad programming practice. For some complex code, it 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 iteration of the loop, 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 used in combination to form algorithms for solving any logic problem. This process is called structured programming.
Amazon app for android 2.3.6. Product Features. Customers are able to shop millions of products on any of Amazon's sites around the world from a single app.Use Alexa to help you shop—just use your voice to search for products on Amazon.
In C, both if statements and while loops rely on the idea of Boolean expressions. Here is a simple C program demonstrating an if statement:
#include int main() { int b; printf('Enter a value:'); scanf('%d', &b); if (b < 0) printf('The value is negativen'); return 0; }
Advertisement
What Is Looping In Programming
![Benefits of looping in programming Benefits of looping in programming](/uploads/1/1/9/4/119401217/834891827.jpg)
Advertisement
This program accepts a number from the user. It then tests the number using an if statement to see if it is less than 0. If it is, the program prints a message. Otherwise, the program is silent. The (b < 0) portion of the program is the Boolean expression. C evaluates this expression to decide whether or not to print the message. If the Boolean expression evaluates to True, then C executes the single line immediately following the if statement (or a block of lines within braces immediately following the if statement). If the Boolean expression is False, then C skips the line or block of lines immediately following the if statement.
Here's slightly more complex example:
Vinyl express r series 2 software download. In this example, the else if and else sections evaluate for zero and positive values as well.
Here is a more complicated Boolean expression:
This statement says, 'If the value in variable x equals the value in variable y, and if the value in variable j is greater than the value in variable k, then set the variable z to 1, otherwise set the variable q to 10.' You will use if statements like this throughout your C programs to make decisions. In general, most of the decisions you make will be simple ones like the first example; but on occasion, things get more complicated.
Notice that C uses to test for equality, while it uses = to assign a value to a variable. The && in C represents a Boolean AND operation.
Here are all of the Boolean operators in C:
You'll find that while statements are just as easy to use as if statements. For example:
This causes the two lines within the braces to be executed repeatedly until a is greater than or equal to b. The while statement in general works as illustrated to the right.
C also provides a do-while structure:
The for loop in C is simply a shorthand way of expressing a while statement. For example, suppose you have the following code in C:
You can convert this into a for loop as follows:
Note that the while loop contains an initialization step (x=1), a test step (x<10), and an increment step (x++). The for loop lets you put all three parts onto one line, but you can put anything into those three parts. For example, suppose you have the following loop:
![Looping Looping](https://www.sitesbay.com/cpp/images/control-statement/while-loop.png)
Looping Statement
You can place this into a for statement as well:
C++ Looping Through Vector
It is slightly confusing, but it is possible. The comma operator lets you separate several different statements in the initialization and increment sections of the for loop (but not in the test section). Many C programmers like to pack a lot of information into a single line of C code; but a lot of people think it makes the code harder to understand, so they break it up.