Question

I need help programming this question using C language.

This program uses input data entered in command line at the same time when the command or .exe file is entered. They are called command-line arguments. Because everything entered in command line is taken as a string, these arguments including the command itself or the .exe file name are stored in an array of char pointers, each pointer points to the first character of a string (i.e., argument). The inputs can be positive, negative, or zero as input data to the program. Duplicate numbers are allowed.

Requirements of main()

1. Each run, the main() of the program will first print the total input numbers it receives. Because this should not include the command or program name itself, this value must be argc-1, assuming argc is the first parameter of main().
2. Then, main() will retrieve these input numbers from its 2nd input parameter, say, argv, and call the functions below in the given order to perform several simple arithmetic functions. For each function call, main() consistently passes the total input numbers it receives (e.g., argc-1) plus its own 2nd parameter, argv, to the function.
3. main() will print the result or return of each function call. All numbers must be printed with three decimal positions.
4. If the program is executed with no numbers entered, main() should display an error message "You must enter at least one number after program name." and stop execution.

Below are prototypes of each function for your design and implementation.

• float min(int total, char *data[total]);  // it returns the minimum of data[1]~data[total]
  Note 1: The first element of the array, i.e., data[0] is the command or .exe file name.
  Note 2: Each element of data[ ] is a string and needs to be converted to floating-point type. Consider the use of atof() (in stdlib.h) for this purpose. When it gets an invalid input that cannot be converted, it always returns zero. For example,
  • atof("xy44.55") returns 0
  • atof(".aa55") returns 0
  • atof("22.33xy44.55") returns 22.33 and ignores the rest part till end
• float min2(int total, char *data[total]);  // it returnsthe second minimum of data[1]~data[total]
• float max(int total, char *data[total]);  // it returns the maximum of data[1]~data[total]
• float max2(int total, char *data[total]);  // it returns the second maximum of data[1]~data[total]
• void sum_avg(int total, char *data[total], float *, float *);  // it returns the sum and average of data[1]~data[total] through its 3rd and 4th parameters, respectively.

Answer 1

// NOTE: In the case when second minimum/maximum do not exist, program will output a large/small number

#include <stdio.h>

#include <stdlib.h>

#define inf 100000

float min(int total, char *data[total])

{

float minValue = inf; // to store minimum number

for(int i = 1; i < total; i++)

{

float cur = atof(data[i]); // current number

if(minValue > cur)

minValue = cur;

}

return minValue;

}

float min2(int total, char *data[total])

{

float small; // minimum number

float s_small; // second minimum number

small = s_small = inf;

for(int i = 1; i < total; i++)

{

float cur = atof(data[i]);

if(small > cur)

{

s_small = small;

small = cur;

}

if(s_small > cur && cur != small)

{

s_small = cur;

}

}

return s_small;

}

float max(int total, char *data[total])

{

float maxValue = -inf; // to store largest number

for(int i = 1; i < total; i++)

{

float cur = atof(data[i]); // current number

if(maxValue < cur)

maxValue = cur;

}

return maxValue;

}

float max2(int total, char *data[total])

{

float large; // maxixum number

float s_large; // second maxixum number

large = s_large = -inf;

for(int i = 1; i < total; i++)

{

float cur = atof(data[i]);

if(large < cur)

{

s_large = large;

large = cur;

}

if(s_large < cur && cur != large)

{

s_large = cur;

}

}

return s_large;

}

void sum_avg(int total, char *data[total], float *sum, float *avg)

{

*sum = 0;

for(int i = 1; i < total; i++)

{

float cur = atof(data[i]);

(*sum) += cur;

}

(*avg) = (*sum)/(total - 1);

}

int main(int argc, char *argv[])

{

if(argc == 1)

{

printf("You must enter at least one number after program name.\n");

return 0;

}

printf("Numbers given: ");

for(int i = 1; i < argc; i++)

printf("%s ", argv[i]);

printf("\n");

printf("Minimum among them is: %f\n", min(argc, argv));

printf("Second minimum among them is: %f\n", min2(argc, argv));

printf("Maximum among them is: %f\n", max(argc, argv));

printf("Second maximum among them is %f\n", max2(argc, argv));

float sum = 0, avg = 0;

sum_avg(argc, argv, &sum, &avg);

printf("Sum of all numbers: %f\n", sum);

printf("Average of all numbers: %f\n", avg);

}