Here is a program which will print out the message.
This is a C program
main()
{
printf("This is a C program\n");
}
Though the program is very simple, a few points are worthy of note.
Every C program contains a function called main. This is the start point of the program.
main() declares the start of the function, while the two curly brackets show the start and finish of the function. Curly brackets in C are used to group statements together as in a function, or in the body of a loop. Such a grouping is known as a compound statement or a block.
printf("This is a C program\n");
prints the words on the screen.
The text to be printed is enclosed in double quotes.
The \n at the end of the text tells the program to print a newline as part of the output.
Most C programs are in lower case letters. You will usually find upper case letters used in preprocessor definitions (To be dealt with later) or inside quotes as parts of character strings. C is case sensitive, that is, it recognises a lower case letter and it's upper case equivalent as being different.
While useful for teaching, such a simple program has few practical uses. Let us consider something rather more practical. The following program will print a conversion table for weight in pounds (U.S.A. Measurement) to pounds and stones (Imperial Measurement) or Kilograms (International).