Question

A series of numerical values have been obtained from a temperature sensor operating in a refrigeration unit. You have been tasked to use the C programming language to develop a program which will query the data series to compute a statistical summary. Upload your C source file to answer the question. The following conditions apply:

• Your program will read data via the standard input stream, and generate a report to the standard output stream.

• The data will be supplied in a plain text file.

• Numeric values are represented as decimal-format integers, separated by white space.

• Values of interest occupy the range {-10,…,30}.

• Due to sampling errors, the series also contains outliers – integers which fall outside the range of interest.

• Your program must parse the input file and count the number of occurrences of each value in the range of interest, ignoring any value outside that range.

• It should produce a statistical summary containing:

  • The lowest occurrence count, and all values for which the occurrence count is equal to the lowest count.

  • The second-lowest occurrence count, and all values for which the occurrence count is equal to the second-lowest count.

  • A complete listing showing the number of occurrences of each value in the range of interest.

• You are advised to use the code skeleton below as the starting point for your solution.

  #include <stdio.h>
  #include <stdlib.h>
  #include <limits.h>
  
  #define MAX_VAL 30
  #define MIN_VAL -10
  
  // Declare and initialise any additional global variables here, as required.
  
  void process(int x) {
      // Process one value here.
  }
  
  void post_process() {
      // Compute derived results here.
  }
  
  void print() {
      // Print results here
  }
  
  int main(void) {
      int x;
      while (1 == scanf("%d", &x)) {
          process(x);
      }
      post_process();
      print();
      return 0;
  }

• The program should process any data file correctly, but to help in your development, sample input data file sample.txt is provided below:

  -6 23 29 15 32 39 -13 12 24 -7 33 32 40 22 35 -2 20 25 27 36 -18 27 -7 35 -11 25 -16 24 8 10 31 10 18 3 31 2 4 -2 40 -18 18 -1 -8 33 21 -19 -8 21 14 -14 23 32 -8 12 -18 30 -2 -4 37 29 -18 37 8 24 32 10 32 -12 6 14 28 30 13 -13 30 -11 22 20 32 22 16 36 29 -8 13 -19 13 -6 -8 37 1 -10 -14 -14 34 -9 -1 21 -13 5 -8 24 -4 31 3 15 38 -8 -13 11 5 21 25 -13 6 22 40 -11 13 -16 30 -18 -12 28 11 -6 10 12 -10 -14 40 20 -2 -5 -16 -17 4 -12 10 24 -12 27 15 1 37 1 6 -2 14 20

• When compiled as program example and executed with the following command:

  cat sample.txt | ./example

  your program will ideally produce this output:

  The lowest count is 0, at -3, 0, 7, 9, 17, 19, 26
  The second-lowest count is 1, at -9, -5, 2, 16
  The complete histogram is:
  -10 -> 2
  -9 -> 1
  -8 -> 7
  -7 -> 2
  -6 -> 3
  -5 -> 1
  -4 -> 2
  -3 -> 0
  -2 -> 5
  -1 -> 2
  0 -> 0
  1 -> 3
  2 -> 1
  3 -> 2
  4 -> 2
  5 -> 2
  6 -> 3
  7 -> 0
  8 -> 2
  9 -> 0
  10 -> 5
  11 -> 2
  12 -> 3
  13 -> 4
  14 -> 3
  15 -> 3
  16 -> 1
  17 -> 0
  18 -> 2
  19 -> 0
  20 -> 4
  21 -> 4
  22 -> 4
  23 -> 2
  24 -> 5
  25 -> 3
  26 -> 0
  27 -> 3
  28 -> 2
  29 -> 3
  30 -> 4

Answer 1

Complete code in C:-

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

// Defining macros
#define MAX_VAL 30
#define MIN_VAL -10

// Defingin global variables
// count is an array of size 41, it stores occurence of each number in range
// range is [-10, 30] so i am adding 10 in every number to make it non negative.
int count[41];
// 'Min' for getting minimum occurence
int Min = 100000;
// 'secondMin' is for getting second minimum occurence.
int secondMin = 100000;

// Processing a number, incrementing its count.
void process(int x) {
   if(x >= MIN_VAL && x <= MAX_VAL) {
       count[x+10]++;
   }
}

// Getting minimum and second minimum occurence value
void post_process() {
   for(int i = 0; i < 41; i++) {
       if(count[i] < Min) {
           secondMin = Min;
           Min = count[i];
       }
   }
}

// Printing data
void print() {
   printf("The lowest count is %d, at ", Min);
   for(int i = 0; i < 41; i++) {
       if(count[i] == Min) {
           printf("%d, ", i-10);
       }
   }
   printf("\n");
   printf("The second-lowest count is %d, at ", secondMin);
   for(int i = 0; i < 41; i++) {
       if(count[i] == secondMin) {
           printf("%d, ", i-10);
       }
   }
   printf("\n");
   printf("The complete histogram is:\n");
   for(int i = 0; i < 41; i++) {
       printf("%d -> %d\n", i-10, count[i]);
   }
}

int main(void) {
   // Variable 'x' will be used to read a number from text file.
   int x;
   // Initializing 'count[]' with all zeros.
   for(int i = 0; i < 41; i++) {
       count[i] = 0;
   }
   // Reading input number and processing them using process() function
   while(scanf("%d", &x) == 1) {
       process(x);
   }
   // Calling 'post_process()' function
   post_process();
   // Calling 'print()' function.
   print();
   return 0;
}

Screenshot of output:-