Array sorting
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The document discusses different sorting algorithms like selection sort and bubble sort. It provides examples of how selection sort and bubble sort work on sample arrays. It also provides C++ code to implement selection sort and bubble sort to sort 5 random numbers entered by the user in ascending order. Selection sort works by selecting the smallest element from the unsorted part and swapping it with the element in the first index of unsorted array. Bubble sort works by repeatedly comparing adjacent elements and swapping them if they are in wrong order.
![University Institute of Information Technology, PMAS-AAUR
Lecture 10: Programming Fundamentals:2012
int array[5], i, j, temp;
cout<< "Enter five integers" << endl;
for(i=0; i<5; i++)
{
cin>>array[i];
}
cout<<"The array in Actual Order n"<<endl;
for(i=0; i<5; i++)
{
cout<<array[i]<<" ";
}
for(i=0; i<5; i++)
for(j=i+1; j<5; j++)
if(array[i]>array[j])
{
temp = array[i];
array[i] = array[j];
array[j] = temp;
}
cout<<endl;
cout<<"The array in Sorted Ordern ";
for(i=0; i<5; i++)
{
cout<<array[i]<<" ";
}
getch();
}
6](https://image.slidesharecdn.com/arraysorting-190324141831/85/Array-sorting-6-320.jpg)
![University Institute of Information Technology, PMAS-AAUR
Lecture 10: Programming Fundamentals:2012
main()
{
int array[5], i, j, temp;
cout<< "Enter five integers" << endl;
for(i=0; i<5; i++)
{
cin>>array[i];
}
cout<<"The array in Actual Order n"<<endl;
for(i=0; i<5; i++)
{
cout<<array[i]<<" ";
}
for(i=0; i<5; i++)
for(j=0; j<4; j++)
if(array[j]>array[j+1])
{
temp = array[j];
array[j] = array[j+1];
array[j+1] = temp;
}
cout<<endl;
cout<<"The array in Sorted Ordern ";
for(i=0; i<5; i++)
{
cout<<array[i]<<" ";
}
getch();
} 11](https://image.slidesharecdn.com/arraysorting-190324141831/85/Array-sorting-11-320.jpg)
Array sorting
- 1. University Institute of Information Technology, PMAS-AAUR Lecture 10: Programming Fundamentals:2012Lecture 01: Programming Fundamentals Lecture 10 Sorting 1
- 2. University Institute of Information Technology, PMAS-AAUR Lecture 10: Programming Fundamentals:2012 Sorting Arrays • The process of arranging the values of an array in particular order is called sorting. • Two Types of sorting: • Ascending Order: The smallest value is stored in the first location of an array. The largest value is stored at the last position of an array. 15 25 33 47 51 • Descending Order: The largest value is stored in the first location of an array. The smallest value is stored at the last position of an array. 51 47 33 25 15 2
- 3. University Institute of Information Technology, PMAS-AAUR Lecture 10: Programming Fundamentals:2012 3 Given an array of length n, – Search elements 0 through n-1 and select the smallest • Swap it with the element in location 0 – Search elements 1 through n-1 and select the smallest • Swap it with the element in location 1 – Search elements 2 through n-1 and select the smallest • Swap it with the element in location 2 – Search elements 3 through n-1 and select the smallest • Swap it with the element in location 3 – Continue in this fashion until there’s nothing left to search
- 4. University Institute of Information Technology, PMAS-AAUR Lecture 10: Programming Fundamentals:2012 4 Example and analysis of selection sort • The selection sort might swap an array element with itself--this is harmless, and not worth checking for • Analysis: – The outer loop executes n-1 times – The inner loop executes about n/2 times on average (from n to 2 times) – Work done in the inner loop is constant (swap two array elements) – Time required is roughly (n- 1)*(n/2) – You should recognize this as O(n2) 7 2 8 5 4 2 7 8 5 4 2 4 8 5 7 2 4 5 8 7 2 4 5 7 8
- 5. University Institute of Information Technology, PMAS-AAUR Lecture 10: Programming Fundamentals:2012 Selection Sort Program that take 5 random values from user in an array and sort it in ascending order. 5
- 6. University Institute of Information Technology, PMAS-AAUR Lecture 10: Programming Fundamentals:2012 int array[5], i, j, temp; cout<< "Enter five integers" << endl; for(i=0; i<5; i++) { cin>>array[i]; } cout<<"The array in Actual Order n"<<endl; for(i=0; i<5; i++) { cout<<array[i]<<" "; } for(i=0; i<5; i++) for(j=i+1; j<5; j++) if(array[i]>array[j]) { temp = array[i]; array[i] = array[j]; array[j] = temp; } cout<<endl; cout<<"The array in Sorted Ordern "; for(i=0; i<5; i++) { cout<<array[i]<<" "; } getch(); } 6
- 7. University Institute of Information Technology, PMAS-AAUR Lecture 10: Programming Fundamentals:2012 Bubble Sort • In the bubble sort, as elements are sorted they gradually "bubble" (or rise) to their proper location in the array, like bubbles rising in a glass of soda. • The bubble sort repeatedly compares adjacent elements of an array. – The first and second elements are compared and swapped if out of order. – Then the second and third elements are compared and swapped if out of order. – This sorting process continues until the last two elements of the array are compared and swapped if out of order. 7
- 8. University Institute of Information Technology, PMAS-AAUR Lecture 10: Programming Fundamentals:2012 • When this first pass through the array is complete, the bubble sort returns to elements one and two and starts the process all over again. • So, when does it stop? • The bubble sort knows that it is finished when it examines the entire array and no "swaps" are needed (thus the list is in proper order). • The bubble sort keeps track of occurring swaps by the use of a flag. 8
- 9. University Institute of Information Technology, PMAS-AAUR Lecture 10: Programming Fundamentals:2012 • The table below follows an array of numbers before, during, and after a bubble sort for descending order. • A "pass" is defined as one full trip through the array comparing and if necessary, swapping, adjacent elements. • Several passes have to be made through the array before it is finally sorted. 9 Array at beginning: 84 69 76 86 94 91 After Pass #1: 84 76 86 94 91 69 After Pass #2: 84 86 94 91 76 69 After Pass #3: 86 94 91 84 76 69 After Pass #4: 94 91 86 84 76 69 After Pass #5 (done): 94 91 86 84 76 69
- 10. University Institute of Information Technology, PMAS-AAUR Lecture 10: Programming Fundamentals:2012 Program that take 5 random values from user in an array and sort it in ascending order, using bubble sort. 10
- 11. University Institute of Information Technology, PMAS-AAUR Lecture 10: Programming Fundamentals:2012 main() { int array[5], i, j, temp; cout<< "Enter five integers" << endl; for(i=0; i<5; i++) { cin>>array[i]; } cout<<"The array in Actual Order n"<<endl; for(i=0; i<5; i++) { cout<<array[i]<<" "; } for(i=0; i<5; i++) for(j=0; j<4; j++) if(array[j]>array[j+1]) { temp = array[j]; array[j] = array[j+1]; array[j+1] = temp; } cout<<endl; cout<<"The array in Sorted Ordern "; for(i=0; i<5; i++) { cout<<array[i]<<" "; } getch(); } 11