While , For , Do-While Loop
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While, for, and do-while loops in C allow code to be repeatedly executed. The while loop repeats as long as a condition is true. The do-while loop executes the statement block first and then checks the condition, repeating until it is false. The for loop allows initialization of a counter variable, a condition to test on each iteration, and an increment expression to modify the counter between iterations. All three loops repeat zero or more times until their condition becomes false.
While , For , Do-While Loop
- 1. Topic : While , For , Do-While Loop Guided By : Branch : Batch :
- 2. Name ENROLLMENT NO. Abhishek Chokshi 140120109005 Raj Shah Kaveesh Raval 140120109054 140120109016
- 3. Repetition statements allow us to execute a statement multiple times Often they are referred to as loops Like conditional statements, they are controlled by boolean expressions There are three kinds of repetition statements:
- 4. The syntax of while statement in C: while (loop repetition condition) statement Loop repetition condition is the condition which controls the loop. The statement is repeated as long as the loop repetition condition is true. A loop is called an infinite loop if the loop repetition condition is always true.
- 5. Logical expression that determines whether the action isto be executed while ( Expression) Action Action to be iteratively performed until logical expression isfalse
- 6. A while statement has the following syntax: while ( condition ){ statement; } • If the condition is true, the statement is executed • Then the condition is evaluated again, and if it is still true, the statement is executed again • The statement is executed repeatedly until the condition becomes false
- 8. An example of a while statement: int count = 1; while (count <= 5){ System.out.println (count); count++; } • If the condition of a while loop is false initially, the statement is never executed • Therefore, the body of a while loop will execute zero or more times
- 10. The syntax of the do-while statement in C: do statement while (loop repetition condition); The statement is first executed. If the loop repetition condition is satisfied, the statement is repeated else, the repetition of the loop is stopped.
- 11. Syntax do Action while (Expression) Semantics ◦ Execute Action ◦ If Expression is true then execute Action again ◦ Repeat this process until Expression evaluates to false Action is either a single statement or a group of statements within curly braces Action true false Expression
- 15. /* Find an even number input */ do{ printf(“Enter a value:n”); scanf(“%d”,&num); }while(num%2!=0) printf(“n%d”,num); This loop will repeat if the user inputs odd number.
- 16. The syntax of for statement in C: for (initialization expression; loop repetition condition; update expression) statement The initialization expression set the initial value of the loop control variable. The loop repetition condition test the value of the loop control variable. The update expression update the loop control variable.
- 17. A for statement has the following syntax: for ( initialization ; condition ; increment ){ statement; } The initialization is executed once before the loop begins The statement is executed until the condition becomes false The increment portion is executed at the end of each iteration
- 19. A for loop is functionally equivalent to the following while loop structure: initialization; while ( condition ){ statement; increment; }
- 20. An example of a for loop: for (int count=1; count <= 5; count++){ System.out.println (count); } • The initialization section can be used to declare a variable • Like a while loop, the condition of a for loop is tested prior to executing the loop body • Therefore, the body of a for loop will execute zero or more times
- 21. The increment section can perform any calculation • A for loop is well suited for executing statements a specific number of times that can be calculated or determined in advance for (int num=100; num > 0; num -= 5){ System.out.println (num); }
- 22. Each expression in the header of a for loop is optional If the initialization is left out, no initialization is performed If the condition is left out, it is always considered to be true, and therefore creates an infinite loop ◦ We usually call this a “forever loop” If the increment is left out, no increment operation is performed
- 23. Remember the break keyword that we used to stop a switch statement from executing more than one statement? break can also be used to exit an infinite loop But it is almost always best to use a well- written while loop