Variables and Arithmetic expressions

Now we see what are variables and arithmetic expressions in C language.

1) We have  discussed  the  structure of a C program in previous section.Now let us discuss about variables and arithmetics in this section

2)There are two types of variables global variables, local variables.In C, all variables must be declared before they are used in the program.

3) A declaration announces the properties of variables; it consists of a name and a list of variables, such as

  int  add,sub;

  int top,bottom;

In the above one int means integer type which takes any constants like add =4 if we give int add=2.2 there will be an error which says wrong declaration, we have to give correct declaration for variables

4)Unlike integer(int),there are some types they are

Character(char)--which prints a single character constant this should be declared in '' this way

Float(float)--which prints floating point constant suppose if we divided 12 by 32 the result will be

0.375,and we store this value to c by giving int type then we get answer as 0 because it will

not  consider the numbers after the point if we give float type it gives the exact answer

So these are important data types there are some more like double,string which we discuss later

4)To detect this types by the compiler we have following things

  

     %d  print as decimal integer

     %c  prints as character

     %s  prints character string

     %6d  print as decimal integer, at least 6 characters wide

     %f  print as floating point

     %6f  print as floating point, at least 6 characters wide

     %.2f  print as floating point, 2 characters after decimal point  

     %6.2f   print as floating point, at least 6 wide and 2 after decimal point

5)Next we come to arithmetic expressions these are known to every one the arithmetic expressions are like addition(+),

subtraction(-),multiplication(*),division(/).

6)These expressions are very familiar to all so these expressions can be used in the C programming but multiplication and division have a higher prescedence than

addition and subtraction