© Manzur
Ashraf
Objective:
Learn
the Data Files.
Scope:
The
student should know the following:
Tips: (Please
read out following tips very carefully)
FILE
*inp, *outp; //
Makes cells named inp and outp
for storage of file pointers.
inp=fopen(“num.dat”, “r”);//It opens num.dat as an input file, storing file pointer in inp.
outp= fopen(“num.out”, “w”); //
It opens num.out as an output file and stores
file
pointer in outp.
fscanf(inp, “%d
%d”, &mid, &low); // It copies
input data from file num.dat into the
type int variable mid
and low.
fprintf(outp, “%d %d
%d”, high,mid,low) ; //
It stores in the file num.out a line
containing the values of high , mid, and low.
fclose(inp); //
Closes created input file num.dat
fclose(outp); //
Closes newly created output file num.out
Solved
Example :
/* Calculates the area and circumference of a circle given a
radius
value from file c: circle.dat .
Stores results in c: circle.out
*/
#include <stdio.h>
#define PI 3.14159
int
main(void)
{
double radius, /* input - radius of a circle */
area, /* output -
area of a circle */
circum; /*
output - circumference of a circle */
FILE *inp, /*
pointer to input file */
*outp; /*
pointer to output file */
/*
Open the input file */
inp = fopen("c:circle.dat", "r");
/*
Open the output file */
outp = fopen("c:circle.out", "w");
/* Read the
radius from circle.dat data file file */
fscanf(inp, "%lf", &radius);
/*
Stores (Saves ) following fprinf
statement’s O/P in circle.out output file */
fprintf(outp, "The radius is %.2f\n", radius);
/*
Calculate the area
*/
area = PI * radius * radius;
/*
Calculate the circumference */
circum = 2 * PI * radius;
/*
Following fprintf statements Stores the area and
circumference in
output
file circle.out
*/
fprintf(outp, "The area is %.2f\n", area);
fprintf(outp,
"The circumference is %.2f\n", circum);
/*
Close input and output files files */
fclose(inp);
fclose(outp);
return (0);
} //
end of main
Excursuses:
Problem#1:
Compile
and Execute program given in solved example and understand it.
Now
modify it to store three different values of radius in data file circle.dat and calculate area and circumference for
these three different radius of circle present in data
file and store these out put in samle.out
file.
(Note :Use for loop)
Problem#2:
Write
a program that generates a data file that contains a table for square roots of numbers
from 1 to n. The user should enter the value of n from key board.
Evaluation:
Your
grade will depend on your active participation, individual efforts and seriousness during the lab.