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Difference between revisions of "C++ for new friends"
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('std::endl' writes a newline and flushes stdout, there is no reason to use it in the example, plus it just adds more confusion.) |
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+ | '''It is recommended to use an IDE, for a tutorial on how to set one up click''' [http://www.cprogramming.com/code_blocks/ HERE] <br /> | ||
+ | Other great resource for learning [http://www.learncpp.com/ C++] from the ground up. | ||
+ | |||
+ | == Printing text to the screen == | ||
+ | |||
+ | <nowiki> | ||
+ | //Text that starts with "//" is ignored by the compiler | ||
+ | //This is the library that allows you to use the "cout" and "endl" objects | ||
+ | #include <iostream> | ||
+ | |||
+ | // int main is where you will be writing your code example | ||
+ | // int main(){code goes here} | ||
+ | int main() | ||
+ | { | ||
+ | // std::cout is sending the text to your screen | ||
+ | // note: 'std::' means you are using a member of the namespace 'std' | ||
+ | // more on that later. | ||
+ | std::cout << "This text will appear on your sceen\n"; | ||
+ | std::cout << "This text will appear on your sceen\n"; | ||
+ | // note: all statements must end with a ; such as above | ||
+ | |||
+ | |||
+ | return 0; | ||
+ | } | ||
+ | </nowiki> | ||
+ | |||
+ | ---- | ||
+ | |||
+ | |||
+ | == Using Data == | ||
+ | |||
+ | <nowiki> | ||
+ | #include <iostream> | ||
+ | |||
+ | int main() | ||
+ | { | ||
+ | // Numbers in C (or C++) can be stored in variables | ||
+ | // Each type can store a different type of data | ||
+ | // For example an int is created by typing keyword int followed by a name, for this example bill | ||
+ | int bill; //this int can store Integers -3 -2 -1 0 1 2 3 etc | ||
+ | bool tom; //can store true or false | ||
+ | float jim; //can store a decimal | ||
+ | char tommy; //this takes characters such as 'x' or 'b' | ||
+ | |||
+ | // variables can be created with no data and set later in the program such as here | ||
+ | bill = 5; | ||
+ | tom = true; | ||
+ | jim = 1.5; | ||
+ | tommy = 'b'; | ||
+ | |||
+ | // just to prove everything works we will print these to the screen | ||
+ | std::cout << "BIL " << bill << '\n'; | ||
+ | std::cout << "TOM " << tom << '\n'; | ||
+ | std::cout << "JIM " << jim << '\n'; | ||
+ | std::cout << "TOMMY "<< tommy << '\n'; | ||
+ | // note: tom will appear as 1 or 0 depending on the true/false state | ||
+ | |||
+ | return 0; | ||
+ | } | ||
+ | </nowiki> | ||
+ | |||
+ | ---- | ||
+ | |||
+ | == Conditions == | ||
+ | |||
+ | <nowiki> | ||
+ | #include <iostream> | ||
+ | |||
+ | int main() | ||
+ | { | ||
+ | |||
+ | int bill = 5; | ||
+ | char tommy = 'b'; | ||
+ | // the if statement will look if the condition inside its brackets is true, | ||
+ | // if it is it will run the block of code below | ||
+ | // we are using the Equal to operator "==" to check if bill is equal to 5 | ||
+ | |||
+ | // other operators include | ||
+ | // != Not equal to | ||
+ | // > Greater than | ||
+ | // <= Less than or equal to | ||
+ | // >= Greater than or equal to | ||
+ | |||
+ | if(bill == 5) | ||
+ | { | ||
+ | tommy = 'X'; | ||
+ | // because bill is equal to 5 tommy will become X | ||
+ | } | ||
+ | |||
+ | if(bill == 6) | ||
+ | { | ||
+ | tommy = 'Y'; | ||
+ | //because bill is not equal to 6 this code is ignored | ||
+ | } | ||
+ | |||
+ | std::cout << "TOMMY " << tommy << '\n'; | ||
+ | |||
+ | return 0; | ||
+ | } | ||
+ | </nowiki> | ||
+ | |||
+ | ---- | ||
+ | |||
+ | == Loops == | ||
+ | |||
+ | <nowiki> | ||
+ | #include <iostream> | ||
+ | |||
+ | int main() | ||
+ | { | ||
+ | int bill = 5; | ||
+ | char tommy = 'b'; | ||
+ | |||
+ | // like if, the while loop will run code if the condition is true | ||
+ | // unlike if, while loops do not stop until the condition becomes false | ||
+ | // below we used the Not equal to operator to check if bill is not equal to 0 | ||
+ | while (bill != 0) | ||
+ | { | ||
+ | //while bill is not equal to 0 the loop will run and print out tommy | ||
+ | std::cout << "TOMMY " << tommy << '\n'; | ||
+ | |||
+ | //the loop will also reduce bill by 1 each time it runs: | ||
+ | bill--; | ||
+ | //thanks to the decrement operator "bill--" bill could also be Incremented with "bill++" | ||
+ | } | ||
+ | |||
+ | return 0; | ||
+ | } | ||
+ | </nowiki> | ||
+ | |||
+ | [[Category:Programming]] | ||
+ | [[Category:Tutorials]] | ||
+ | [[Category:HowTo]] | ||
+ | [[Category:Programming languages]] |
Latest revision as of 12:45, 19 November 2023
It is recommended to use an IDE, for a tutorial on how to set one up click HERE
Other great resource for learning C++ from the ground up.
Printing text to the screen
//Text that starts with "//" is ignored by the compiler //This is the library that allows you to use the "cout" and "endl" objects #include <iostream> // int main is where you will be writing your code example // int main(){code goes here} int main() { // std::cout is sending the text to your screen // note: 'std::' means you are using a member of the namespace 'std' // more on that later. std::cout << "This text will appear on your sceen\n"; std::cout << "This text will appear on your sceen\n"; // note: all statements must end with a ; such as above return 0; }
Using Data
#include <iostream> int main() { // Numbers in C (or C++) can be stored in variables // Each type can store a different type of data // For example an int is created by typing keyword int followed by a name, for this example bill int bill; //this int can store Integers -3 -2 -1 0 1 2 3 etc bool tom; //can store true or false float jim; //can store a decimal char tommy; //this takes characters such as 'x' or 'b' // variables can be created with no data and set later in the program such as here bill = 5; tom = true; jim = 1.5; tommy = 'b'; // just to prove everything works we will print these to the screen std::cout << "BIL " << bill << '\n'; std::cout << "TOM " << tom << '\n'; std::cout << "JIM " << jim << '\n'; std::cout << "TOMMY "<< tommy << '\n'; // note: tom will appear as 1 or 0 depending on the true/false state return 0; }
Conditions
#include <iostream> int main() { int bill = 5; char tommy = 'b'; // the if statement will look if the condition inside its brackets is true, // if it is it will run the block of code below // we are using the Equal to operator "==" to check if bill is equal to 5 // other operators include // != Not equal to // > Greater than // <= Less than or equal to // >= Greater than or equal to if(bill == 5) { tommy = 'X'; // because bill is equal to 5 tommy will become X } if(bill == 6) { tommy = 'Y'; //because bill is not equal to 6 this code is ignored } std::cout << "TOMMY " << tommy << '\n'; return 0; }
Loops
#include <iostream> int main() { int bill = 5; char tommy = 'b'; // like if, the while loop will run code if the condition is true // unlike if, while loops do not stop until the condition becomes false // below we used the Not equal to operator to check if bill is not equal to 0 while (bill != 0) { //while bill is not equal to 0 the loop will run and print out tommy std::cout << "TOMMY " << tommy << '\n'; //the loop will also reduce bill by 1 each time it runs: bill--; //thanks to the decrement operator "bill--" bill could also be Incremented with "bill++" } return 0; }