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Switch case and looping new

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Fundamentals of programming: Switch case and looping

Fundamentals of programming: Switch case and looping

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    Switch case and looping new Switch case and looping new Presentation Transcript

    • A final requirement for programming http://eglobiotraining.com
    • We first define the word “programming”, it is acomputer language programmers use to developapplications, scripts, or other set of instructions for acomputer to execute. programming is instructing a computer to dosomething for you with the help of a programminglanguage. The role of a programming language can bedescribed in two ways:• Technical: It is a means for instructing a Computer to perform Tasks• Conceptual: It is a framework within which we organize our ideas about things and processes. http://eglobiotraining.com
    • As an individual, I have learned that programming is avery broad because it composes many scripts, applications andcan be used to run a program that has been part of theprogramming language. A programming language should both provide means todescribe primitive data and procedures and means to combineand abstract those into more complex ones. The distinction between data and procedures is not thatclear cut. In many programming languages, procedures can bepassed as data (to be applied to ``real data) and sometimesprocessed like ``ordinary data. Conversely ``ordinary data canbe turned into procedures by an evaluation mechanism. http://eglobiotraining.com
    • At first, programming is confusing because you haveso much to understand about codes that will enable to runa program. Programming has applications and programdevelopment, the best example for this is the Internetbowser… Programming is a creative process done byprogrammers to instruct a computer on how to do a task.Fundamentally programs manipulate numbers and text.These are the building blocks of all programs.Programming languages let you use them in differentways, e.g adding numbers, etc… or storing data on disk forlater retrieval. http://eglobiotraining.com
    • You have to consider languages to run or write yourown program, most demanded language in programming isthe DEV C++ (a full-featured Integrated DevelopmentEnvironment (IDE)). C++ is one of the most used programminglanguages in the world. Also known as "C with Classes".New to programming or thinking about it? It might surpriseyou to know that there are many programmers whoprogram just for fun and it can lead to a job. http://eglobiotraining.com
    • Switch case statements are a substitute for longif statements that compare a variable to several"integral" values ("integral" values are simply values thatcan be expressed as an integer, such as the value of achar). http://eglobiotraining.com
    • basic format for using switchcase: switch ( <variable> ) {case this-value: Code to execute if <variable> == this-value break;case that-value: Code to execute if <variable> == that-value break;...default: Code to execute if <variable> does not equal the value following any ofthe cases break;}The value of the variable given into switch is compared to the value followingeach of the cases, and when one value matches the value of the variable,the computer continues executing the program from that point. http://eglobiotraining.com
    • The condition of a switch statement is avalue. The case says that if it has the value ofwhatever is after that case then do whateverfollows the colon. The break is used to break outof the case statements. An important thing tonote about the switch statement is that the casevalues may only be constant integralexpressions. http://eglobiotraining.com
    • “Break” is a keyword that breaks out of thecode block, usually surrounded by braces, whichit is in. In this case, break prevents the programfrom falling through and executing the code in allthe other case statements. http://eglobiotraining.com
    • The default case is optional, but it is wise toinclude it as it handles any unexpected cases.Switch statements serves as a simple way towrite long if statements when the requirementsare met. Often it can be used to process inputfrom a user. http://eglobiotraining.com
    • This shows how would you use a Switch in a Program #include <iostream> using namespace std; void playgame() { cout << "Play game called"; } void loadgame() } cout << "Load game called"; void playmultiplayer() { cout << "Play multiplayer game called"; } int main() { int input; cout<<"1. Play gamen"; cout<<"2. Load gamen"; cout<<"3. Play multiplayern"; cout<<"4. Exitn"; cout<<"Selection: "; cin>> input; switch ( input ) { case 1: // Note the colon, not a semicolon playgame(); break; case 2: // Note the colon, not a semicolon loadgame(); break; case 3: // Note the colon, not a semicolon playmultiplayer(); break; case 4: // Note the colon, not a semicolon cout<<"Thank you for playing!n"; break; default: // Note the colon, not a semicolon cout<<"Error, bad input, quittingn"; break; } cin.get(); } http://eglobiotraining.com
    • That program will compile, but cannot be run untilthe undefined functions are given bodies, but itserves as a model (albeit simple) for processinginput. If you do not understand this then try mentallyputting in if statements for the case statements. Defaultsimply skips out of the switch case construction andallows the program to terminate naturally. If you do notlike that, then you can make a loop around the wholething to have it wait for valid input. You could easily makea few small functions if you wish to test the code. http://eglobiotraining.com
    • Loops are used to repeat a block ofcode. Being able to have your programrepeatedly execute a block of code is one ofthe most basic but useful tasks inprogramming -- many programs or websitesthat produce extremely complex output (suchas a message board) are really onlyexecuting a single task many times. http://eglobiotraining.com
    • (They may be executing a small numberof tasks, but in principle, to produce a list ofmessages only requires repeating theoperation of reading in some data anddisplaying it.) Now, think about what thismeans: a loop lets you write a very simplestatement to produce a significantly greaterresult simply by repetition. http://eglobiotraining.com
    • One Caveat: before going further, you shouldunderstand the concept of C++s true andfalse, because it will be necessary when working withloops (the conditions are the same as with if statements). Three types of Loops: for, while, and do.. http://eglobiotraining.com
    • FORFor ( variable initialization; condition; variable update ) { Code to execute while the condition is true} http://eglobiotraining.com
    • The variable initialization allows you to either declare a variableand give it a value or give a value to an already existing variable.Second, the condition tells the program that while the conditionalexpression is true the loop should continue to repeat itself. Thevariable update section is the easiest way for a for loop to handlechanging of the variable. It is possible to do things like x++, x = x +10, or even x = random ( 5 ), and if you really wanted to, you couldcall other functions that do nothing to the variable but still have auseful effect on the code. Notice that a semicolon separates each of these sections, thatis important. Also note that every single one of the sections may beempty, though the semicolons still have to be there. If the conditionis empty, it is evaluated as true and the loop will repeat untilsomething else stops it. http://eglobiotraining.com
    • Example: #include <iostream> using namespace std; // So the program can see cout and endl int main() { // The loop goes while x < 10, and x increases by one every loop for ( int x = 0; x < 10; x++ ) { // Keep in mind that the loop condition checks // the conditional statement before it loops again. // consequently, when x equals 10 the loop breaks. // x is updated before the condition is checked. cout<< x <<endl; } cin.get(); } This program is a very simple example of a for loop. x is set to zero, while x is less than 10 it calls cout<< x <<endl; and it adds 1 to x until the condition is met. Keep in mind also that the variable is incremented after the code in the loop is run for the first time. http://eglobiotraining.com
    • WHILEThe basic structure: While ( condition ) { Code to execute while the condition is true } The true represents a boolean expression which could be x == 1 or while ( x != 7 ) (x does not equal 7). It can be any combination of boolean statements that are legal. Even, (while x ==5 || v == 7) which says execute the code while x equals five or while v equals 7. Notice that a while loop is the same as a for loop without the initialization and update sections. However, an empty condition is not legal for a while loop as it is with a for loop. http://eglobiotraining.com
    • Example: #include <iostream> using namespace std; // So we can see cout and endl int main() { int x = 0; // Dont forget to declare variables while ( x < 10 ) { // While x is less than 10 cout<< x <<endl; x++; // Update x so the condition can be met eventually } cin.get(); } The easiest way to think of the loop is that when it reaches the brace at the end it jumps back up to the beginning of the loop, which checks the condition again and decides whether to repeat the block another time, or stop and move to the next statement after the block. http://eglobiotraining.com
    • DO..WHILE are useful for things that want to loop at least once.The Structure: do { } while ( condition ) ; http://eglobiotraining.com
    • Notice that the condition is tested at the end of theblock instead of the beginning, so the block will beexecuted at least once. If the condition is true, we jumpback to the beginning of the block and execute it again. Ado..while loop is basically a reversed while loop. Awhile loop says "Loop while the condition is true, andexecute this block of code", a do..while loop says"Execute this block of code, and loop while thecondition is true". http://eglobiotraining.com
    • Example: #include <iostream> using namespace std; int main() { int x; x = 0; do { // "Hello, world!" is printed at least one time // even though the condition is false cout<<"Hello, world!n"; } while ( x != 0 ); cin.get(); } Keep in mind that you must include a trailing semi-colon after the while in the above example. A common error is to forget that a do..while loop must be terminated with a semicolon (the other loops should not be terminated with a semicolon, adding to the confusion). Notice that this loop will execute once, because it automatically executes before checking the condition. http://eglobiotraining.com
    • http://eglobiotraining.com
    • LOOPING STATEMENT 1#include <iostream>int main(){ using namespace std; // nSelection must be declared outside do/while loop int nSelection; do { cout << "Please make a selection: " << endl; cout << "1) Addition" << endl; cout << "2) Subtraction" << endl; cout << "3) Multiplication" << endl; cout << "4) Division" << endl; cin >> nSelection; } while (nSelection != 1 && nSelection != 2 && nSelection != 3 && nSelection != 4); // do something with nSelection here // such as a switch statement return 0;} http://eglobiotraining.com
    • LOOPING STAEMENT 2#include <iostream>using namespace std; int main(){ int nSelection; double var1, var2; do { cout << "Please make a selection: " << endl; cout << "1) Addition" << endl; cout << "2) Subtraction" << endl; cout << "3) Multiplication" << endl; cout << "4) Division" << endl; cin >> nSelection; } while (nSelection != 1 && nSelection != 2 && nSelection != 3 && nSelection != 4); if (nSelection == 1) { cout << "Please enter the first whole number "; cin >> var1; cout << "Please enter the second whole number "; cin >> var2; cout << "The result is " << (var1+var2) << endl; } http://eglobiotraining.com
    • LOOPING STATEMENT 3 if (nSelection == 2) { cout << "Please enter the first whole number "; cin >> var1; cout << "Please enter the second whole number "; cin >> var2; cout << "The result is " << (var1-var2) << endl; } if (nSelection == 3) { cout << "Please enter the first whole number "; cin >> var1; cout << "Please enter the second whole number "; cin >> var2; cout << "The result is " << (var1*var2) << endl; } if (nSelection == 4) { cout << "Please enter the first whole number "; cin >> var1; cout << "Please enter the second whole number "; cin >> var2; cout << "The result is " << (var1/var2) << endl; } return 0; } http://eglobiotraining.com
    • LOOPING STATEMENT 3#include <iostream>using namespace std; int main(){ int nSelection; double var1, var2; while (1) { do { cout << "Please make a selection: " << endl; cout << "1) Addition" << endl; cout << "2) Subtraction" << endl; cout << "3) Multiplication" << endl; cout << "4) Division" << endl; cout << "5) Exit" << endl; cin >> nSelection; } while (nSelection != 1 && nSelection != 2 && nSelection != 3 && nSelection != 4 && nSelection != 5); if (nSelection == 1) { cout << "Please enter the first whole number "; cin >> var1; cout << "Please enter the second whole number "; cin >> var2; cout << "The result is " << (var1+var2) << endl; } http://eglobiotraining.com
    • LOOPING STATEMENT 4 else if (nSelection == 2) { cout << "Please enter the first whole number "; cin >> var1; cout << "Please enter the second whole number "; cin >> var2; cout << "The result is " << (var1-var2) << endl; } else if (nSelection == 3) { cout << "Please enter the first whole number "; cin >> var1; cout << "Please enter the second whole number "; cin >> var2; cout << "The result is " << (var1*var2) << endl; } else if (nSelection == 4) { cout << "Please enter the first whole number "; cin >> var1; cout << "Please enter the second whole number "; cin >> var2; cout << "The result is " << (var1/var2) << endl; }else { return 0; } }} http://eglobiotraining.com
    • LOOPING STATEMENT 5#include <iostream>using namespace std; // So the program can see cout and endlint main(){ // The loop goes while x < 10, and x increases by one every loop for ( int x = 0; x < 10; x++ ) { // Keep in mind that the loop condition checks // the conditional statement before it loops again. // consequently, when x equals 10 the loop breaks. // x is updated before the condition is checked. cout<< x <<endl; } cin.get();} http://eglobiotraining.com
    • LOOPING STATEMENT 6#include <iostream>using namespace std;int main(){ int x; x = 0; do { // "Hello, world!" is printed at least one time // even though the condition is false cout<<"Hello, world!n"; } while ( x != 0 ); cin.get();} http://eglobiotraining.com
    • LOOPING STATEMENT 7#include <iostream>using namespace std;int main (){int n;cout << "Enter the starting number > ";cin >> n;while (n>0) {cout << n << ", ";--n;}cout << "FIRE!n";return 0;} http://eglobiotraining.com
    • SWITCH CASE 1SWITCH CASE#include <iostream>using namespace std;int main (){ int score; cout << "What was your score?"; cin >> score; if (score <= 25) { cout << "nOuch, less than 25...!"; } http://eglobiotraining.com
    • SWITCH CASE 2else if (score <= 50) { cout << "nYou score aint great mate.."; } else if (score <= 75) { cout << "nYour pretty good, wel done man!"; } else if (score <= 100) { cout << "nYou got to the top!!!"; } http://eglobiotraining.com
    • SWITCH CASE 3 else { cout << "nYou cant score higher than 100!!! Cheater!!!!"; } cin.ignore(); cin.get(); return 0;} http://eglobiotraining.com
    • SWITCH CASE 4#include <iostream>using namespace std;int main(){cout << "Enter a number between 1 and 5!" << endl;int number;cin >> number;if(number == 1){cout << "one";}else if(number == 2){cout << "two";}else if(number == 3){cout << "three";}else if(number == 4){cout << "four";}else if(number == 5){cout << "five";}else{cout << number << " is not between 1 and 5!";}cout << endl;system("pause");} http://eglobiotraining.com
    • SWITCH CASE 5#include <iostream>using namespace std;int main(){int price_before_discount, RM, dozen, total_price;cout<< "How much is the price before discount for 1 dozen boxes of tissue?n";cout<<"RM ";cin>>price_before_discount;cout<<"nn";cout<< "How many dozen boxes of tissue you buy?n";cin>>dozen;cout<<"nn";switch (dozen){total_price = ((price_before_discount*dozen) * (95/100));case 1: cout<< "Total price is RM ";cout<<RM;cout<<"nn";break;total_price = ((price_before_discount*dozen) * (88/100));case 2: cout<< "Total price is RM ";cout<<RM;cout<<"nn";break;total_price = ((price_before_discount*dozen) * (75/100));case 3: cout<< "Total price is RM ";cout<<RM;cout<<"nn";break;total_price = ((price_before_discount*dozen) * (60/100));case 4 : cout<< "Total price is RM ";cout<<RM;cout<<"nn";break;total_price = ((price_before_discount*dozen) * (40/100));default : cout<< "Total price is RM ";cout<<RM;cout<<"nn";}return 0;} http://eglobiotraining.com
    • SWITCH CASE 6#include <stdlib.h>#include <stdio.h>int main(void) { int n; printf("Please enter a number: "); scanf("%d", &n); switch (n) { case 1: { printf("n is equal to 1!n"); break; } case 2: { printf("n is equal to 2!n"); break; } case 3: { printf("n is equal to 3!n"); break; } default: { printf("n isnt equal to 1, 2, or 3.n"); break; } } system("PAUSE"); return 0;} http://eglobiotraining.com
    • SWITCH CASE 7#include <iostream>using namespace std;int main(void){ char grade; cout << "Enter your grade: "; cin >> grade; switch (grade) { case A: cout << "Your average must be between 90 - 100" << endl; break; case B: cout << "Your average must be between 80 - 89" << endl; break; case C: cout << "Your average must be between 70 - 79" << endl; break; case D: cout << "Your average must be between 60 - 69" << endl; break; default: cout << "Your average must be below 60" << endl; } return 0;} http://eglobiotraining.com
    • http://eglobiotraining.com
    • In this looping statement, I used “while” looping, and I choose to showMDAS just as an example for the program to run. If logicalExpression evaluates to true, the statement executes. The logicalExpression is reevaluated. The body of the loop continues to executeuntil the logicalExpression is false http://eglobiotraining.com
    • I have came up with this by just starting to write this code:#include <iostream> and then enter the succeeding codes,compiled and run. http://eglobiotraining.com
    • I noticed that sometimes if the program does not run, it is becausesome braces are not included and I accidentally put braces on thesame line and it causes the program not to read its contents.Programming is sensitive, when there is missing variable orbraces or some words it does not run. http://eglobiotraining.com
    • When I learned that programming is very sensitive and at thesame time very detailed when it comes to entering codes, Imake sure that it is clear means that I put everything importantcodes in it so that the program would run. http://eglobiotraining.com
    • So much codes that should be entered that even the spaces areneeded programming is very specific that whatever you haveentered in to it you should specify because when the statement isfalse it wouldn’t let you run the program, I have experienced itbefore I arrived at this result. http://eglobiotraining.com
    • Because of so many experiences I had before this program run, Ifound programming is also interesting for the more you arepracticing to make a program run, the more questions that cameup in my mind and try something that will fit to this or entering newcodes to make matrix etc… that I know is possible. http://eglobiotraining.com
    • In this switch case missing out a break statement causes control tofall through to the next case label. Switches can always be replacedby nested if-else statements, but in some cases this may be moreclumsy. Each break statement terminates theenclosing switch statement. Control flow continues with the firststatement http://eglobiotraining.com
    • Unlike if-then and if-then-else statements, the switch statement canhave a number of possible execution paths, A switch works withthe byte, short, char, and int primitive data types. http://eglobiotraining.com
    • The switch statement evaluates its expression, then executes allstatements that follow the matching case label. http://eglobiotraining.com
    • The switch statement can include any number of case instances, butno two case constants within the same switch statement can havethe same value. Execution of the statement body begins at theselected statement and proceeds until the jump-statement transferscontrol out of the case body. http://eglobiotraining.com
    • Submitted by:Tarun, April G. BM10203 http://eglobiotraining.com