I have to write a program in C and have it read an input text file that I created and output to an output file and show the original numbers and then sort them. I have most of it working, but it gives me an error when trying to get past a certain number in just reading the original input. Here is my code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//function prototypes
void sortNumbers(int *num, int count);
void swap(int *nums, int i, int j);
//main function
int main(int argc, char *argv[])
{
//declare the variables
int *numbers;
int count = 0, i = 0;
char input[20], output[20];
FILE *fileIn, *fileOut;
//allocate the default size of array to maximum of 100
numbers = (int *)malloc(sizeof(int));
//check the number of arguments at command line
if (argc < 2)
{
printf("Please provide the input and output text file names as ./a.out name1 name2 \n");
return 0;
}
//read the file names from command line
else
{
sscanf(argv[1], "%s", input);
sscanf(argv[2], "%s", output);
}
//open the files
fileIn = fopen(input, "r");
fileOut = fopen(output, "w");
//condition to check whether the input file and output
//file are able to open or not. If not print the error message
if (fileIn == NULL)
{
printf("Input file %s cannot be opened.\n", input);
return 0;
}
else if (fileOut == NULL)
{
printf("Output file %s cannot be opened. \n", output);
return 0;
}
//read the data from the file
else
{
fscanf(fileIn, "%d", &numbers[i]);
printf("%d\n", numbers[i]);
fprintf(fileOut, "%d\n", numbers[i]);
while (!feof(fileIn))
{ i++;
numbers = (int *)realloc(numbers,(i)*sizeof(int));
fscanf(fileIn, "%d", &numbers[i]);
printf("%d\n", numbers[i]);
fprintf(fileOut, "%d\n", numbers[i]);
}
}
count = i;
//close the files
fclose(fileIn);
printf("\n");
//sort the elements in the array
sortNumbers(numbers, count);
fprintf(fileOut,"\nElements after sorting are: \n");
printf("\nElements after sorting are: \n");
//print the elements to the console and to the
//output file
for(i=0;i<count;i++)
{
fprintf(fileOut,"%d \n", numbers[i]);
printf("%d \n", numbers[i]);
}
fclose(fileOut);
return 0;
}
//sort algorithm using selection sort
void sortNumbers(int *num, int count)
{
for (int i = 0; i < count; ++i)
{
int minIndex = i;
for (int j = i + 1; j < count; ++j)
{
if(num[j]<num[minIndex])
minIndex = j;
}
swap(num, minIndex, i);
}
}
//swap function
void swap(int *nums, int i, int j)
{
int temp = nums[i];
nums[i] = nums[j];
nums[j] = temp;
}
