Struggling with arrays and for loops

[geross23]

have a program in which I used arrays in functions. It wants me to enter up to a 100000 random numbers and sort them. When I run my program it keeps looping and I'm not sure why. Can anyone please look at the program and help me, thanks.



#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;

/**************************** function prototypes ******************************/
//performs selection sort
void selectionSort(int a[], int numberUsed);
//Precondition: numberUsed <= declared size of the array a.
//The array elements a[0] through a[numberUsed - 1] have values.
//Postcondition: The values of a[0] through a[numberUsed - 1] have
//been rearranged so that a[0] <= a[1] <= ... <= a[numberUsed - 1].

void swapValues(int& v1, int& v2);
//Interchanges the values of v1 and v2.

int indexOfSmallest(const int a[], int startIndex, int numberUsed);
//Precondition: 0 <= startIndex < numberUsed. References array elements have values.
//Returns the index i such that a[i] is the smallest of the values
//a[startIndex], a[startIndex + 1], ..., a[numberUsed - 1].

void generateArray(int a[], int size, int& numberGenerated);

void showArray(const int a[], int numberUsed);

const int SIZE = 100000;

/****************************** main function ********************************/

int main()
{
int data[SIZE], numberUsed = 0;
char response;

generateArray(data, SIZE, numberUsed);

showArray(data, numberUsed);

long beforeSort = (long) time(0);

selectionSort (data, numberUsed);

long afterSort= (long) time(0);

cout <<"Sorting the array using selection sort...\n"
<<"Time taken to sort " <<numberUsed <<" numbers is " <<afterSort - beforeSort <<endl;
cout <<"seconds. " <<"Would you like to see the sorted array? (y/n): ";
cin >>response;
cout <<"The array after being sorted is: \n";

if(response == 'y' || response =='Y')
showArray (data, numberUsed);

return 0;
}

/***** supplied function definitions (Do not modify codes below this line) *****/
void selectionSort(int a[], int numberUsed)
{
int indexOfNextSmallest;
for (int start = 0; start < numberUsed - 1; start++)
{ //start is the starting index of the unsorted segment
indexOfNextSmallest = indexOfSmallest(a, start, numberUsed);
swapValues(a[start], a[indexOfNextSmallest]);
}
}

int indexOfSmallest(const int a[], int startIndex, int numberUsed)
{
int min = a[startIndex],
indexOfMin = startIndex;
for (int index = startIndex + 1; index < numberUsed; index++)
if (a[index] < min)
{
min = a[index];
indexOfMin = index;
//min is the smallest of a[startIndex] through a[index]
}
return indexOfMin;
}

void swapValues(int& v1, int& v2)
{
int temp;
temp = v1;
v1 = v2;
v2 = temp;
}

void generateArray (int a[], int size, int& numberGenerated)
{
int i;
char response;

cout << "How many random integers do you want to generate?: ";
cin >> numberGenerated;

if(numberGenerated >= size)
numberGenerated = size;

cout <<"We have generated " << numberGenerated << " random integers. \n"
<<"Would you like to see the generated array? (y/n): ";
cin >>response;

if(response == 'y' || response =='Y')
cout <<"The array generated is: \n";

srand((unsigned int)time(0));
for(i = 0; i <= (numberGenerated-1); i++)
{
a[i] = rand();
}
}

void showArray (const int a[], int numberUsed)
{
for (int i = 0; i < numberUsed; i++)
cout << a[i] << "\t";
cout <<endl;
}

[MrHutch]

There's a bunch of issues with missing braces throughout your code. Stuff like if statements and for loops not having braces after them.

I'd suggest sorting all of those out first.

[geross23]

Thank you for the help, I think I figured it out.