Output Of Real Numbers | tutorial for beginners

Output Of Real Numbers

The output of a real number may be displayed in decimal notation the following  format specification: %w.pf The integer w indicates the minimum number of positions
that are to be used for the display of the value and integer ‘p’ indicates the number of digits to be displayed after the decimal point. The value when displayed is rounded to ‘p’ decimal places and printed right justified in the field o f w columns. The default precision is 6 decimal places. we can
also display a real number in exponential notation by using %w.pe     
   The display takes the form [-]m.nnnne[+ or -]xx  where the length of the string of n’s is specified by the precision p. The default precision is 6.The field width w should satisfy the condition     
              w>=p+7.
   The value will be of the rounded off and printed right justified in the field of w columns.Padding
the leading blanks with zeros and printing with left justification is also possible by introducing 0 or – before the field width specifier w.
  The following example illustrate the output of the number
y=98.7654 under different format specifications:

1.   FORMAT
     printf("%7.4f",y);
     OUTPUT:
   
9 8 . 7 6 5 4


                           2.   FORMAT
                               printf("%7.2f",y);
OUTPUT:
9 9 8 . 7 7



                           3. FORMAT
                               printf("%-7.2f",y)
OUTPUT:
9 9 8 . 7 7




                            4.  FORMAT
                               printf("%f",y)
OUTPUT:
9 9 8 . 7 6 5 4



                              5.   FORMAT
                               printf("%10.2e",y)
OUTPUT:
9 9 . 8 8 e + 0 1



                               6.  FORMAT
                               printf("%11.4e",-y)
OUTPUT:
9 - 9 . 8 7 6 5 e + 0 1



                               7. FORMAT
                               printf("%-10.e",y)
OUTPUT:
9 9 8 8 e + 0 1




                            8. FORMAT
                               printf("%e",y)
OUTPUT:
9 9 8 7 6 5 4 0 e + 0 1




      Some systems also supports a special field at run-time.This takes the following form :
         printf("%*.*f",width,precision,number);
    In this case both the field width and the precision are given as arguments which will supply the values for w and p.
for example
        printf("%7.2f",number);
   The advantage of this format is that the values for width and precision may be supplied at runtime ,thus making the format a dynamic one.
For example the above statement can be used as follows:

     int width=7;
     int precision=2;         
    ----------------
    ---------------
    printf("%*.*f",width,precision,number);

Program: All the options of printing a real number
           /* printing of real numbers*/
           main()
           {
            float y=98.7654;
            printf("% 7.4f\n",y);
            printf("%f\n",y);
            printf("%7.2f\n",y);
            printf("%-7.2f\n",y);
            printf("%0. 72Ff\n",y);
            printf("%*.*f",7,2,y);
            printf("\n");
            printf("%10.2e\n",y);

            printf("%12.4e\n",-y);
            printf("%-10.2e\n",y);
            printf("%e\n",y);
           }

Output:   98.7654
                98.765404
                     98.77
               98.77
               0098.77
               98.77

          9.88e+001
         -9.8765e+001
           9.876540e+001

Printing of single  characters: 
          A single character can be displayed in a desired position using the format
      %wc   
       The character will be displayed right-justified in the field of w columns. We can make the display left- justified by placing a minus sign before the integer w.The