C Tutorial
2. Let's Compute
The following program computes a table of the sine function for angles between
0 and 360 degrees.
We will learn basic calculations and we learn how we
can use deferent methods of deferent library header files in this example
.Basically we are calculating the sine values from 0 to 360.
Before exampling this example first you must know types of different variable.
C uses the following standard variable types:
int -> integer variable
short -> short integer
long -> long integer
float -> single precision real (floating point) variable
double -> double precision real (floating point) variable
char -> character variable (single byte)
The compilers checks for consistency in the types of all variables used in any
code. This feature is intended to prevent mistakes, in particular in mistyping
variable names. Calculations done in the math library routines are usually
done in double precision arithmetic (64 bits on most workstations). The actual
number of bytes used in the internal storage of these data types depends on
the machine being used.
The printf function can be instructed to print integers, floats and strings
properly. The general syntax is
printf( "format", variables );
#include < stdio.h>
#include < math.h>
void main()
{
int angle_degree;
double angle_radian, pi, value;
// Print a message
printf ("\nCompute a table of the sine function\n\n");
// obtain pi
pi = 4.0*atan(1.0);
printf ( " Value of PI = %f \n\n", pi );
printf ( " angle Sine \n" );
angle_degree=0;
// initial angle value
// scan over angle
while ( angle_degree <= 360 )
// loop until angle_degree > 360
{
angle_radian = pi * angle_degree/180.0 ;
value = sin(angle_radian);
printf ( " %3d %f \n ", angle_degree, value );
angle_degree = angle_degree + 10;
// increment the loop index
}
}
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where "format" specifies the conversation specification and variables is a list
of quantities to print. Some useful formats are
%.nd integer (optional n = number of columns; if 0, pad with zeroes)
%m.nf float or double (optional m = number of columns,
n = number of decimal places)
%ns string (optional n = number of columns)
%c character
\n \t to introduce new line or tab
\g ring the bell (``beep'') on the terminal.
Example descriptions:
1.Include header files:
#include < stdio.h>
#include < math.h>
These two header files must be included first.
first is included for printf()and main() methods as these methods are defined in
this header file.
Second <math.h> header file is included for sin function. In <math.h> header file
all mathematical methods eg sin(),cose(),sqrt() etc. are define to use them we need
to include this header file at top most in our progarm.
We are using while loop for printing and calculating value of sin from 0
to 360.