CS140: Intro to CSAn Overview of Programming in C (part 3)

by Erin Chambers

Getting startedPlease log in to the computer, click on the startup menu (located in bottom left corner)Select Utilities -> Kate to open a text editor

Running our programWe need to compile our C program using the compiler called ccThe compiler then outputs an executable file which will run our program, usually called a.outTo run it, open up a Konsole (the little black screen icon at the bottom), type cc filename.c, then type ./a.out at a command prompt

RecapNumbers - int, floatOutput printfInput - scanfIf-else statementsWhile loopsCharacters - char

CharactersThe data type char stores a single characterEach character is actually represented as a number, just like with ASCIITo read or write a character variable, use %c

Basic char program#include main(void){char letter;

printf(Enter a character:);scanf(%c,&letter);printf(You entered %c, letter);return 0;}

Fun with char#include main(void){char letter; \\initialize letter to be a character

\\Read in a characterprintf(Enter a character:);scanf(%c, &letter);

\\Print out the character and its associated numberprintf(The character you entered is %c \n, letter);printf(Its C number is %d, letter);return 0;}

Char tricks#include

main(void){ char letter; int number;

//Prompt user to enter a character printf("Enter a letter:"); scanf("%c", &letter);

//Find the next letter in the alphabet and print it number = letter; number = number + 1; printf("The next letter is %c\n", number);

return 0;}

A shortcutThe c command getchar() reads the next character from the inputSo letter = getchar(); is equivalent to scanf(%c, &letter);

Count the length of a message#include main(void){char ch;int length = 0;

//Prompt the user for a message

//Read the first character of the message

//while loop to count how the message is

//print length of message

return 0;}