Question

Write a program in C that reads 20 float numbers from a file. The values are stored in a vector (1-dimensional array). Find and display the smallest number, the second smallest number, and the third smallest number of the set. Use only these libraries: stdio.h, stdlib.h, math.h, and string.h. Below is an example of the input file (in1.txt) and the resulting output file (output.txt).

In1.txt:

3.14       4.05       -3.73      4.13       1.32

-2.21      0.46       4.57       4.64       -3.42

4.57       -0.14      3.00       -3.58      -0.78

2.92       4.594     1.55       -4.64      3.49

Output.txt:

The smallest number is: -4.64

The second smallest number is: -3.73

The third-smallest number is: -3.58

Answer 1

C Program:

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

int main()
{
//File Pointer
FILE *fp, *ofp;

//Array declaration
float arr[20];
float firstMin, secondMin, thirdMin;
int i=0;

//Opening file
fp = fopen("in1.txt", "r");
ofp = fopen("output.txt", "w");

//Checking file opening status
if(fp == NULL)
{
printf("File Opening failed....");
return -1;
}

//Reading data from file
while(fscanf(fp, "%f", &arr[i]) == 1)
{
//Incrementing i
i++;
}

//Finding first second and third min elements
firstMin = arr[0];
secondMin = arr[0];
thirdMin = arr[0];

for(i=0; i<20; i++)
{
//First check
if(arr[i] < firstMin)
{
//Adjusting minimum values
thirdMin = secondMin;
secondMin = firstMin;
firstMin = arr[i];
}
//Second Check
else if(arr[i] < secondMin)
{
//Adjusting minimum values
thirdMin = secondMin;
secondMin = arr[i];
}
//Third Check
else if(arr[i] < thirdMin)
{
//Adjusting minimum values
thirdMin = arr[i];
}
}

//Writing results to file
fprintf(ofp, "The smallest number is: %.2f \n The second smallest number is: %.2f \n The third-smallest number is: %.2f", firstMin, secondMin, thirdMin);

//Closing files
fclose(fp);
fclose(ofp);

return 0;
}

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Sample Run: