How to Learn Coding

• Some of the more common variables include int , char , and float . Each variable will store a different type of data.

 float x ; character name ; _ int a , b , c , d ;

• Note that you can declare multiple variables on the same line, as long as they are of the same type. You just need to separate the variable names with commas.
• Like many lines in C, each line declaring a variable needs to end with a semicolon.

 #include <stdio.h> int main () { int x ; printf ( "Enter a number:" ); scanf ( "%d" , & x ); printf ( "You entered %d" , x ); getchar (); return 0 ; }

• The string "%d" tells scanf to look for integers in user input.
• The & before the variable x tells scanf where to find the variable to replace it, and stores the integers in the variable.
• The last command printf reads the input integer back to the user.

• TRUE and FALSE in C will work differently than you might be used to. The TRUE statement always ends with a non-zero number. When you do the comparison, if the result is TRUE then “1” will be returned. If the result is FALSE, return “0”. Understanding this point will help you understand how IF statements are handled.

 #include <stdio.h> int main () { int age ; printf ( "Please enter your current age: " ); scanf ( "%d" , & age ); if ( age <= 12 ) { printf ( "You're a kid! n " ); } else if ( age < 20 ) { printf ( "Being a teenager is great! n " ); } else if ( age < 40 ) { printf ( "You're still young! n " ); } else { printf ( "The older the ginger, the spicier it gets. n " ); } return 0 ; }

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• The program takes data from the user and passes it through IF statements. If the metric meets the first statement, the first printf statement is returned. If it fails to respond to the first statement, it is passed through ELSE IF statements until it finds a match. If it doesn’t match any statements, it will go through the ELSE statement at the end.

• There are three main types of loops: FOR, WHILE, and DO … WHILE.

 #include <stdio.h> int main () { int y ; for ( y = 0 ; y < 15 ; y ++ ;){ printf ( "%d n " , y ); } getchar (); }

• In the above program, y is set to 0, and the loop continues running as long as the y value is less than 15. Each time the y value is printed, the y value will be added by 1 and the loop will be repeated. again. When y = 15, the loop will be broken.

 #include <stdio.h> int main () { int y ; while ( y <= 15 ){ printf ( "%d n " , y ); y ++ ; } getchar (); }

• The y++ instruction will add 1 to the variable y each time the loop is executed. When the variable y reaches 16 (remember, this loop will continue running as long as the y value is less than or equal to 15), the loop is stopped.

 #include <stdio.h> int main () { int y ; y = 5 ; do { printf ( "Loop is running! n " ); } while ( y != 5 ); getchar (); }

• This loop will display the message even though the condition is FALSE. The variable y is set to 5 and the WHILE loop is set to run when y is not 5, so the loop terminates. The message is printed from when the condition is unchecked until the end.
• The WHILE loop in the DO…WHILE setup must be terminated with a semicolon. This is the only time a loop ends with a semicolon.

• The main() line at the top of all the examples above is a function, for example getchar()
• Functions are essential to making code efficient and readable. Make good use of functions to organize your program.

 int plus ( int x , int y );

• This will create a function that adds two integers ( x and y ) together and then returns the sum which is also an integer.

 #include <stdio.h> int plus ( int x , int y ); int main () { int x ; int y ; printf ( "Enter the two numbers you want to add together: " ); scanf ( "%d" , & x ); scanf ( "%d" , & y ); printf ( "The sum of your numbers is %d n " , plus ( x , y ) ); getchar (); } int plus ( int x , int y ) { return x + y ; }

• Note that the outline is still at the top of the program. This tells the compiler what to expect when the function is called and what the result should be. This is only necessary if you want to define a function at the end of the program. You can put the add() (plus) function before the main() function and the result will be the same without the outline.
• The actual function of the function is defined at the end of the program. The main() function collects integers from the user and then sends them to the add() function for processing. The add() function performs the addition function and then returns the result to main()
• At this point add() has been defined, which can be called anywhere in the program.

• Attend some hack-a-thons if possible. These are events where groups and individuals come up with programs and solutions, and often spur creativity within deadlines. You can meet a lot of good programmers this way, and hack-a-thon competitions are often held around the globe.