Managing input and output operations & Decision making and branching and looping

Managing input and output operations & Decision making and branching and looping

1. UNIT 2 MANAGING INPUT AND OUTPUT OPERATIONS

2. WHAT IS INPUT AND OUTPUT OPERATIONS?

3. statement-x;

4. Switch Statement

5. SYNTAX OF SWITCH STATEMENT

6. EXAMPLE, #include <stdio.h> int main() { int num = 2; switch (num) { case 1: printf("Value is 1\n"); break; case 2: printf("Value is 2\n"); break;

7. case 3: printf("Value is 3\n"); break; default: printf("Value is not 1, 2, or 3\n"); break; } return 0; } OUTPUT: Value is 2

8. ?: Statement in C The conditional operator in C is kind of similar to the if-else statement as it follows the same algorithm as of if-else statement but the conditional operator takes less space and helps to write the if-else statements in the shortest way possible. It is also known as the ternary operator in C as it operates on three operands. Syntax of Conditional/Ternary Operator in C The conditional operator can be in the form, variable = Expression1 ? Expression2 : Expression3; Or the syntax can also be in this form variable = (condition) ? Expression2 : Expression3;

9. EXAMPLE, C Program to Store the greatest of the two Numbers using the ternary operator // C program to find largest among two // numbers using ternary operator #include <stdio.h> int main() { int m = 5, n = 4;

10. (m > n) ? printf("m is greater than n that is %d > %d", m, n) : printf("n is greater than m that is %d > %d", n, m); return 0; } Output m is greater than n that is 5 > 4

11. GOTO STATEMENT The goto statement is used to transfer the program's control to a defined label within the same function. It is an unconditional jump statement that can transfer control forward or backward. The goto keyword is followed by a label. When executed, the program control is redirected to the statement following the label.If the label points to any of the earlier statements in a code, it constitutes a loop. On the other hand, if the label refers to a further step, it is equivalent to a Jump.

12. goto Statement Syntax The syntax of goto statement is − goto label; . . . . . . label: statement; The label is any valid identifier in C. A label must contain alphanumeric characters along with the underscore symbol (_). As in case of any identifier, the same label cannot be specified more than once in a program. It is always followed by a colon (:) symbol. The statement after this colon is executed when goto redirects the program here.

13. Example , #include <stdio.h> int main (){ int i = 11; if (i % 2 == 0){ EVEN: printf("The number is even \n"); goto END; }

14. else{ ODD: printf("The number is odd \n"); } END: printf("End of program"); return 0; } OUTPUT: The number is odd End of program

15. DECISION MAKING AND LOOPING While statement The while Loop is an entry-controlled loop in C programming language. This loop can be used to iterate a part of code while the given condition remains true. Syntax The while loop syntax is as follows: while (test expression) { // body consisting of multiple statements }

16. EXAMPLE, // C program to demonstrate while loop #include <stdio.h> int main() { // Initialization of loop variable int i = 0; // setting test expression as (i < 5), means the loop // will execute till i is less than 5

17. while (i < 5) { // loop statements printf(" Hello \n"); // updating the loop variable i++; } return 0; }

18. OUTPUT: Hello Hello Hello Hello Hello while Loop Structure The while loop works by following a very structured top-down approach that can be divided into the following parts: Initialization: In this step, we initialize the loop variable to some initial value. Initialization is not part of while loop syntax but it is essential when we are using some variable in the test expression

19. Conditional Statement: This is one of the most crucial steps as it decides whether the block in the while loop code will execute. The while loop body will be executed if and only the test condition defined in the conditional statement is true. Body: It is the actual set of statements that will be executed till the specified condition is true. It is generally enclosed inside { } braces. Updation: It is an expression that updates the value of the loop variable in each iteration. It is also not part of the syntax but we have to define it explicitly in the body of the loop.

20. DO Statement (do...while loop) The do…while in C is a loop statement used to repeat some part of the code till the given condition is fulfilled. It is a form of an exit-controlled or post-tested loop where the test condition is checked after executing the body of the loop. Due to this, the statements in the do…while loop will always be executed at least once no matter what the condition is. Syntax of do…while Loop in C do { // body of do-while loop } while (condition);

21. EXAMPLE, // C Program to demonstrate the use of do...while loop #include <stdio.h> int main() { // loop variable declaration and initialization int i = 0; // do while loop do {

22. printf("hello\n"); i++; } while (i < 3); return 0; } OUTPUT: hello hello hello

23. The working of the do…while loop is explained below: When the program control first comes to the do…while loop, the body of the loop is executed first and then the test condition/expression is checked, unlike other loops where the test condition is checked first. Due to this property, the do…while loop is also called exit controlled or post-tested loop. When the test condition is evaluated as true, the program control goes to the start of the loop and the body is executed once more. The above process repeats till the test condition is true. When the test condition is evaluated as false, the program controls move on to the next statements after the do…while loop.

24. FOR STATEMENT ( for Loop in C ) The for loop in C Language provides a functionality/feature to repeat a set of statements a defined number of times. The for loop is in itself a form of an entry-controlled loop. Unlike the while loop and do…while loop, the for loop contains the initialization, condition, and updating statements as part of its syntax. It is mainly used to traverse arrays, vectors, and other data structures. Syntax of for Loop for(initialization; check/test expression; updation) { // body consisting of multiple statements }

25. Structure of for Loop The for loop follows a very structured approach where it begins with initializing a condition then checks the condition and in the end executes conditional statements followed by an updation of values. Initialization: This step initializes a loop control variable with an initial value that helps to progress the loop or helps in checking the condition. It acts as the index value when iterating an array or string. Check/Test Condition: This step of the for loop defines the condition that determines whether the loop should continue executing or not. The condition is checked before each iteration and if it is true then the iteration of the loop continues otherwise the loop is terminated. Body: It is the set of statements i.e. variables, functions, etc that is executed repeatedly till the condition is true. It is enclosed within curly braces { }. Updation: This specifies how the loop control variable should be updated after each iteration of the loop. Generally, it is the incrementation (variable++) or decrementation (variable–) of the loop control variable.

26. EXAMPLE, // C program to demonstrate for loop #include <stdio.h> int main() { int abc = 0; // 'abc' <= 5 is the check/test expression // The loop will function if and only if 'abc' is less // than 5 //'abc++' will increments it's value by this so that the // loop can iterate for further evaluation

27. // conditional statement for ( abc = 1; abc <= 5; abc ++) { // statement will be printed printf(" Hello \n"); } // Return statement to tell that everything executed // safely return 0; }

28. Output : Hello Hello Hello Hello Hello