C++ Buffer is too small Error - c++

Question

Intermittently, Visual Studio throws an exception when running my code. I say intermittently because I've been able to successfully run my code without an error. The error was thrown after I created the function "print_Days."
The exception thrown is:
Debug Assertion Failed!
File: minkernel\crts\ucrt\corecrt_internal_string_templates.h
Line: 81
Expression: (L"Buffer is too small" && 0)
The function reads from a .txt file that has 7 days of the week listed (Monday thru Sunday) and then alphabetically sorts the days in a 2D c-string array (professor is making us use c-string instead of string unfortunately).
Here is all of my code:
#include <iostream>
#include <fstream>
#include <string>
#include <cstring>
using namespace std;
//Constants for 2D array
const int NUM_OF_ROWS = 7; //Seven days listed in the file
const int NUM_OF_COLS = 10; //Longest word is 9 chars long, plus \0
void get_Days(ifstream& file, char days[][NUM_OF_COLS], int rows);
void sort_Days(char days[][NUM_OF_COLS], int rows);
void print_Days(const char days[][NUM_OF_COLS], const int rows);
void get_Days(ifstream& file, char days[][NUM_OF_COLS], int rows) {
//Read from text file and return day
for (int i = 0; i < rows; ++i)
{
file >> days[i];
}
}
void sort_Days(char days[][NUM_OF_COLS], int rows) {
//Sort the array alphabetically
char temp[NUM_OF_COLS];
for (int i = 0; i < rows; i++)
{
for (int j = 0; j < rows; j++)
{
if (strcmp(days[j - 1], days[j]) > 0)
{
strcpy_s(temp, days[j - 1]);
strcpy_s(days[j - 1], days[j]);
strcpy_s(days[j], temp);
}
}
}
}
void print_Days(const char days[][NUM_OF_COLS], const int rows) {
//Print the sorted array to the console
for (int i = 0; i < NUM_OF_ROWS; ++i)
for (int i = 0; i < rows; i++)
{
for (int j = 0; j < NUM_OF_COLS; j++)
{
cout << days[i][j] << endl;
}
}
}
int main() {
//This program reads from a file (days.txt), sorts the days
// alphabetically, and then prints the result to the console.
ifstream infile("days.txt");
char days[NUM_OF_ROWS][NUM_OF_COLS];
if (!infile)
{
cout << "File (days.txt) does not exist." << endl;
return 1;
}
get_Days(infile, days, NUM_OF_ROWS);
infile.close();
sort_Days(days, NUM_OF_ROWS);
print_Days(days, NUM_OF_ROWS);
return 0;
}

Answer 1

A few things are wrong with the code:
sort_Days
The sort_Days algorithm is throwing errors because you are trying to index days[j - 1] when the nested for loop starts with j = 0. So your initial index is out of bounds.
Furthermore, it seems like you are trying to perform bubble sort on the c-style strings, but your bubble sort implementation is incorrect. Please consult this page for how to implement a simple bubble sort. Hint: the for loop conditional, strcmp and strcpy_s indices need some tweaking.
print_Days
Your print_Days function is incorrect. Here is a version that prints out each c-style string instead of each char within the string:
void print_Days(const char days[][NUM_OF_COLS], const int rows)
{
for (int j = 0; j < rows; j++)
{
cout << days[j] << endl;
}
}
You should know that std::cout understands that when you pass it a c-style string (i.e. the char[NUM_OF_COLS] within days), it means you want to print out the whole string up to the null-terminator.
Your for loop termination conditional was also wrong, because you had j < NUM_OF_COLS, whereas days actually is an array with NUM_OF_ROWS elements, and each element is an array of NUM_OF_COLS size. The way you had it had indexing out of bounds of the days array.
And while I am nitpicking
Try not to use using namespace::std;, there are plenty of reasons why you shouldn't..