CS111 Lab Spring 2010

Wednesday, August 4, 2010

topics for final

loops (nested)
arrays (1d, 2d)
functions (pass by ref, by val, arrays)
recursion (tracing recursion)
sorting

Tuesday, August 3, 2010

// dfgdfdfg.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include <iomanip>
#include <string>
#include <fstream>
// within iostream
// istream cin;
// ostream cout;
using namespace std;

bool aComposite[1024] = { true, true };
bool isPrime(int n)
{
    return ! aComposite[n];
}

void setupLookupTable()
{
    for (int i = 2; i < 1024; i++)
    {
        // is this number i am visiting
        // already marked off as composite
        if (aComposite[i] == false)
            for (int j=i+i; j < 1024; j+=i)
                aComposite[j] = true;
    }

}

void print(const int a[], int capacity)
{
    for (int i = 0; i < capacity; i++)
        cout << a[i] << ' ';
    cout << endl;
}

void add(const int a[], const int b[], int c[], int capacity)
{
    for (int i = 0; i < capacity; i++)
        c[i] = a[i] + b[i];
}

void add(const int a[][3], const int b[][3], int c[][3], int rows, int cols)
{
    for (int i = 0; i < rows; i++)
        for (int j = 0; j < cols; j++)
            c[i][j] = a[i][j] + b[i][j];
}

void print(const int C[][3], int rows, int cols)
{
    for (int i = 0; i < rows; i++)
    {
        for (int j = 0; j < cols; j++)
            cout << "[" << setw(3) << C[i][j] << "]";
        cout << endl;
    }
}

//template <int rows, int cols>
//int dotProduct(int (&A)[rows][cols],
//               int (&B)[rows][cols],
//               const int row, const int col)
//{
//    int total = 0;
//    for (int i = 0; i < 3; i++)
//        total += A[row][i] * B[i][col];
//    return total;
//}

//template <int rows, int cols>
//void mmult(int (&A)[rows][cols], int (&B)[rows][cols], int (&C)[rows][cols])
//{
//    for (int i = 0; i < rows; i++)
//        for (int j = 0; j < cols; j++)
//            C[i][j] = dotProduct(A, B, i, j);
//}

int minimumValue(const int a[], const int capacity)
{
    int minValue = a[0];
    for (int i = 1; i < capacity; i++)
        if (a[i] < minValue)
            minValue = a[i];
    return minValue;
}

int minimumPosition(const int a[], const int startPos, const int capacity)
{
    int minPos = startPos;
    for (int i = startPos + 1; i < capacity; i++)
        if (a[i] < a[minPos])
            minPos = i;
    return minPos;
}

void selectionSort(int A[], int capacity)
{
    for (int i = 0; i < capacity; i++)
    {
        int minPos = minimumPosition(A, i, capacity);
        swap(A[i], A[minPos]);
    }
}
void subtract(const int a[], const int b[], int c[], int capacity)
{
    for (int i = 0; i < capacity; i++)
        c[i] = a[i] - b[i];
}

void mult(const int a[], int scalar, int b[], int capacity)
{
    for (int i = 0; i < capacity; i++)
        b[i] = a[i] * scalar;
}
int foo(int *a)
{
    return 0;
}

template <typename T, typename S>
void swap2(T &a, S &b)
{
    T temp = a;
    a = b;
    b = temp;
}

void print(char s[])
{
        for (int i = 0; s[i]; i++)
            cout << s[i];
}

void print2(char *s)
{
        for (; *s; s++)
            cout << *s;
}

int main() {
    char name[10] = "hello";
    char fred[10] = "hello";
strcmp(name, fred)
    if (name < fred)
    if (strcmp(name, fred) < 0)

if (name > fred)
if (strcmp(name, fred) > 0)

if(name == fred)
if (strcmp(name, fred) == 0)

fred = name;
strcpy(fred, name);

    for (int i = 0; name[i] != 0; i++)
        cout << name[i];
    cout << endl;
    print2(name);
    cout << endl;
    fred = name;
    if (name == fred)
    {
    }
    string b = "hi ";
    b += "there";
    //int A[3][3], B[4][3];
    //dotProduct(A, B, 2, 1);

//    int first = 2;
//    float second = 3;
//    swap2<int, int>(first, second);
//    cout << first << " " << second << endl;
//    int v[10];
//    foo(v);
//    foo(&v[0]);
//    cout << v << endl;
//    cout << &v[0] << endl;
//
//
//
//    //setupLookupTable();
//    //for(int k = 0; k < 1024; k++)
//    //    if (isPrime(k))
//    //        cout << k << endl;
//    //string s, t;
//    //int u;
//
//    //ifstream jin;
//    //jin.open("myfirstinput.txt");
//    //jin >> s;
//    //jin >> t;
//    //cout << s << t << endl;
//    //jin.close();
//
//    //ofstream jout;
//    //jout.open("c:/josh/myfirstoutput.txt");
//    //for(int i = 0; i < 10; i++)
//    //    jout << i << " ";
//    //jout << endl;
//    //jout.close();
//    //system("PAUSE");
//
//   int A[3][3] =
//   {
//       { 4, 6, 0},
//       { 6, 0, 1},
//       { -1,3, 5}
//   };
//   int B[3][3] =
//   {
//       { 0, 6, 0},
//       { 1, 0, 1},
//       { 1, 0, 5}
//   };
//   int C[3][3];
//   cout << "DP: " << dotProduct(A, B, 0, 1) << endl;
//    add(A, B, C, 3, 3);
//    print(C, 3, 3);
//
//cout << endl;
//cout << endl;
//cout << endl;
//
//   int x[5] = {3,4,5,2,3};
//   int y[5] = {1,1,0,2,3};
//   int z[5];
//   int a[5];
//
//    // a = x * 6
//   add(x, y, z, 5);
//
//   print(z, 5);
//
//   mult(y, 6, z, 5);
//   print(z, 5);
//
//   return 0;
}

// iterative approach
void insert(int a[], int capacity)
{
    // yank out the element
    int value = a[capacity-1];

    // shift items over
    for (int j = capacity - 2; j >= 0 && a[j] > value; j--)
        a[j+1] = a[j];

    a[j+1] = value;
}

void insertionSort(int a[], int capacity)
{
    for (int i = 1; i <= capacity; i++)
        insert(a, i);

}

to sort an array of size n,
first: sort the array of size n -1
insert element n into that sorted partial result of array n-1

// using recursion
void insertionSort(int a[], int capacity)
{
    if (capacity == 1)
        return;
    insertionSort(a, capacity - 1);
    insert(a, capacity);
}

// strings
c-strings
C++ strings

char name[10] = "hello";
for (int i = 0; name[i] != 0; i++)
    cout << name[i];

Monday, August 2, 2010

int A[4];

A[0] at 100
A[1] at 104
A[2] at 108
A[3] at 112

A[10]
*(A + 10)
memory location 100 + (10 * sizeof int)
void foo(int p[])
{
    for (int i = 0; i < 4; i++)
        cout << *(p+i);
}

int * bar(int p[])
{
    int B[5] = {5, 4, 3, 1, 6};
    B[3] = 7;
    return p;
}

main()
{
int A[4];
for (int i = 0; i < 4; i++)
    cout << A[i] << " ";

for (int i = 0; i < 4; i++)
    cout << *(A+i) << " ";
cout << endl;

foo(A);
int *q = bar(A);
}

template <typename T>
void swap2(T &a, T &b)
{
    T temp = a;
    a = b;
    b = temp;
}

// recursive bubblesort
void bubbleSort(int a[], int capacity)
{
    if (capacity == 1)
        return;
    // do one sweep
    for(int i = 0; i < capacity; i++)
        if (a[i] > a[i+1])
             swap(a[i], a[i+1])

    bubbleSort(a, capacity - 1);
}

// dfgdfdfg.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include <iomanip>
#include <string>
#include <fstream>
// within iostream
// istream cin;
// ostream cout;
using namespace std;

bool aComposite[1024] = { true, true };
bool isPrime(int n)
{
    return ! aComposite[n];
}

void setupLookupTable()
{
    for (int i = 2; i < 1024; i++)
    {
        // is this number i am visiting
        // already marked off as composite
        if (aComposite[i] == false)
            for (int j=i+i; j < 1024; j+=i)
                aComposite[j] = true;
    }

}

void print(const int a[], int capacity)
{
    for (int i = 0; i < capacity; i++)
        cout << a[i] << ' ';
    cout << endl;
}

void add(const int a[], const int b[], int c[], int capacity)
{
    for (int i = 0; i < capacity; i++)
        c[i] = a[i] + b[i];
}

void add(const int a[][3], const int b[][3], int c[][3], int rows, int cols)
{
    for (int i = 0; i < rows; i++)
        for (int j = 0; j < cols; j++)
            c[i][j] = a[i][j] + b[i][j];
}

void print(const int C[][3], int rows, int cols)
{
    for (int i = 0; i < rows; i++)
    {
        for (int j = 0; j < cols; j++)
            cout << "[" << setw(3) << C[i][j] << "]";
        cout << endl;
    }
}

template <int rows, int cols>
int dotProduct(int (&A)[rows][cols],
               int (&B)[rows][cols],
               const int row, const int col)
{
    int total = 0;
    for (int i = 0; i < 3; i++)
        total += A[row][i] * B[i][col];
    return total;
}

template <int rows, int cols>
void mmult(int (&A)[rows][cols], int (&B)[rows][cols], int (&C)[rows][cols])
{
    for (int i = 0; i < rows; i++)
        for (int j = 0; j < cols; j++)
            C[i][j] = dotProduct(A, B, i, j);
}

int minimumValue(const int a[], const int capacity)
{
    int minValue = a[0];
    for (int i = 1; i < capacity; i++)
        if (a[i] < minValue)
            minValue = a[i];
    return minValue;
}

int minimumPosition(const int a[], const int startPos, const int capacity)
{
    int minPos = startPos;
    for (int i = startPos + 1; i < capacity; i++)
        if (a[i] < a[minPos])
            minPos = i;
    return minPos;
}

int selectionSort(int A[], int capacity)
{
    for (int i = 0; i < capacity; i++)
    {
        int minPos = minimumPosition(A, i, capacity);
        swap(A[i], A[minPos];
    }
}
void subtract(const int a[], const int b[], int c[], int capacity)
{
    for (int i = 0; i < capacity; i++)
        c[i] = a[i] - b[i];
}

void mult(const int a[], int scalar, int b[], int capacity)
{
    for (int i = 0; i < capacity; i++)
        b[i] = a[i] * scalar;
}
int foo(int *a)
{
    return 0;
}

template <typename T, typename S>
void swap2(T &a, S &b)
{
    T temp = a;
    a = b;
    b = temp;
}

int main() {
    int A[3][3], B[4][3];
    dotProduct(A, B, 2, 1);

//    int first = 2;
//    float second = 3;
//    swap2<int, int>(first, second);
//    cout << first << " " << second << endl;
//    int v[10];
//    foo(v);
//    foo(&v[0]);
//    cout << v << endl;
//    cout << &v[0] << endl;
//
//
//
//    //setupLookupTable();
//    //for(int k = 0; k < 1024; k++)
//    //    if (isPrime(k))
//    //        cout << k << endl;
//    //string s, t;
//    //int u;
//
//    //ifstream jin;
//    //jin.open("myfirstinput.txt");
//    //jin >> s;
//    //jin >> t;
//    //cout << s << t << endl;
//    //jin.close();
//
//    //ofstream jout;
//    //jout.open("c:/josh/myfirstoutput.txt");
//    //for(int i = 0; i < 10; i++)
//    //    jout << i << " ";
//    //jout << endl;
//    //jout.close();
//    //system("PAUSE");
//
//   int A[3][3] =
//   {
//       { 4, 6, 0},
//       { 6, 0, 1},
//       { -1,3, 5}
//   };
//   int B[3][3] =
//   {
//       { 0, 6, 0},
//       { 1, 0, 1},
//       { 1, 0, 5}
//   };
//   int C[3][3];
//   cout << "DP: " << dotProduct(A, B, 0, 1) << endl;
//    add(A, B, C, 3, 3);
//    print(C, 3, 3);
//
//cout << endl;
//cout << endl;
//cout << endl;
//
//   int x[5] = {3,4,5,2,3};
//   int y[5] = {1,1,0,2,3};
//   int z[5];
//   int a[5];
//
//    // a = x * 6
//   add(x, y, z, 5);
//
//   print(z, 5);
//
//   mult(y, 6, z, 5);
//   print(z, 5);
//
//   return 0;
}

Thursday, July 29, 2010

for (int i = 0; i < n - 1; i++)
    for (int j = 0; j < n - i - 1; j++)
        if (a[j] > a[j+1])
            swap(a[j], a[j+1]);

Wednesday, July 28, 2010

// add two matrices
int A[3][3];
int B[3][3];
int C[3][3];
for (int i = 0; i < 3; i++)
    for (int j = 0; j < 3; j++)
        cout << C[i][j] << " ";

int i =0;
++i

this means: (i = i+1, new value of i)

i++
this means: (temp = i, i = i+ 1, temp)

while(i = 0, i < 10, ++i)
    cout << i << " ";

void swap(int *a, int *b)
{
    int temp;
    temp = *a;
    *a = *b;
    *b = temp;
}

main()
{
    int x = 7;
    int y = 8;
    swap(&x, &y);
    cout << x << " " << y << endl;
}