CPNM LAB PROGRAM-7

 

7. First use an editor to create a file with some integer numbers. Now write a program, which reads these numbers and determines their mean and standard deviation.

                      FLOW CHART :-

Algorithm: 

Step – 1 : Start 

Step – 2 : Initialize sum = 0, sum_sq = 0, count = 0, mean = 0 and sd = 0 

Step – 3 : Open a file ‘mean.dat’ in write mode 

Step – 4 : Check the condition if(fp==NULL) 

Step – 5 : Print the integers 

Step – 6 : To Stop entry press Ctrl + z 

Step – 7 : If end of the input is reached return EOF 

Step – 8 : Close the file 

Step – 9 : Open the file ‘mean.dat’ in read mode 

Step – 10 : Print file to be open if(fp==NULL) condition is true and exit if file ended 

Step – 11 : Print numbers in file 

Step – 12 : If check the condition while end is not reached 

Step – 13 : If true 

                 (i) Read integer numbers from file 

                (ii) Print the number 

               (iii) Increment sum by no. 

               (iv) Increment count by 1. 

                (v) Increment sum by no. * no. 

Step – 14 : Close the file 

Step – 15 : Mean = sum / count 

Step – 16 : Sd = sqrt((sum_sq / count )–(mean * mean)) 

Step – 17 : Print mean, standard deviation 

Step – 18 : Stop 

PROGRAM:

#include<stdio.h>

#include<conio.h>

#include<stdlib.h>

#include<math.h>

 main() 

{ FILE *fp;

int n, count = 0, sum = 0, sumsq = 0; 

float mean = 0.0, sd = 0.0; 

clrscr();

fp = fopen("mean.dat","w"); 

if(fp==NULL)

 {

puts("\n Can't open the file "); 

exit(0); }

printf("\n Enter some numbers. To stop use Ctrl + z :\n"); 

while(scanf("%d",&n)!=EOF) 

{ fprintf(fp,"%d\t",n); }

fclose(fp);

fp = fopen("mean.dat","r");

printf("\n The numbers stored in file : \n"); 

while(fscanf(fp,"%d",&n)!=EOF)

{ count++;

 sum = sum + n;

 printf("%d\t",n); 

  sumsq += n * n;

} 

fclose(fp); 

mean = sum / count; 

printf("\n Mean = %0.2f",mean); 

sd = sqrt((sumsq/count)-(mean*mean)); 

printf("\n standard derivation = %0.2f\n",sd); 

getch(); return 0;

} 

   THIS CODE IS CREATED BY ECE THE WONDERS, HEMU THE SMART

Output: Enter some numbers to stop use Ctrl + z: 

1.2 

2.1 

2.3 

7.8 

5.6 

3.4 

3.1 

9.0 

^Z 

The numbers stored in file : 

1.200000 2.100000 2.300000 7.800000 5.600000 3.400000 3.100000 9.000000 

Mean = 4.31 

Standard derivation = 2.66