hello program

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A simple hello program.(demonstrates the const function in all c programs--the main() function.)

(example-1)

#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
putsf("hello world guess who is writing a c program");
getch();
}
That's it. In all c programs there is a main function which is followed by a { and closed by a } after a return() function.It doesn't have to be return(0) but that depends upon the type of c compiler you have. Check your compiler before you start your programming.

You saw above that printf function is used to print a whole sentence on the screen; but are there functions that will put characters on the screen/take characters: Yes and next is a table of what they are and what they do. Read them and the examples that follow.


getchar() Gets a single character from the input/keyboard.

putchar() Puts a single character on the screen.

The printf function is a function used to print the output to the screen.printf() needs to know if the output is an integer, real,etc

example-2

void main()
{
printf("hello");
}
Assuming hello was defined earlier say by #define hello "Hello!" the output is Hello!. But if the output is an integer then %d has to be attatched to the printf statement.
This above can be shown as printf("I am %d years old",12) which will result in the following result:I am 12 years old
The %d tells that an integer is to be placed here.
Now we will look into a function called scanf().This lets you input from the kewyboard and for that input to be taken by the program and processed.Once again it is important to tell scanf() what type of data is being scanned.
Here is an example of a program that demonstrates both scanf and printf in unison.

example-3

void main() {
int count;
puts("Please enter a number: ");
scanf("%d", &count);
printf("The number is %d",count);
}
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That concludes the first hour of your tutorial.Now this is a list of data type identifiers.

%f=float
%c=char
%s =string
%e=inputs number in scientific notation.
%t=single tab
%
As you saw in the first hour of our tutorial c is a language in which you program using functions. Functions are usually identified by the following characteristic:>> functionname() In c the main() function is essential. Think of it as a constant function for all your programs and all other functions can be accessed from the main().Before I show you how we do that let us have an example where we want to pause a program before the screen is changed. This would involve the foll- owing procedure:>> write a main function then use puts function to put statements on the screen like we did in section 1 above and then before the next set of puts statements declare a pause.
This is how it is done:

example-4

main()
{
puts("hello there");
puts("what is your name?")
pause()
puts("It is nice to meet you")
}
pause();
{
int move_on;
printf("press entere to continue");
move_on=getchar();
return(0);
}

This above will pause until a key is pressed on the keyboard. Granted that the above program makes no sense from a practical point of view but I want to show is the use of another function inside the main function.
C has many functions that comes with it. See your compiler manual to see what you have.Now we are going to look at conditions in c programming:>> the if command and do command.
Here is an example of th if command:

example-5

main()
{
float cost,tax,luxury,total;
luxury=0.0;
printf("Enter the cost of the item: ");
scanf("%f", &cost);
tax=cost*0.06;
if(cost>40000.0)
luxury=cost*0.005;
total=cost+tax+luxury;
printf("the total cost is %0.2f",total);
}