Class Examples 7/17/02
Example #1
----------
#include <iostream.h>

void wordcopy(char word[], char saveword[], int length);
void reverse(char word[], int length);
bool equal(char word[], char word2[], int length);
void swap(char &a, char &b);

void main() {

  char word[20], saveword[20];
 
  cout << "Enter a word, less than 20 letters long.\n";
  cin >> word;
  int length = strlen(word);	
  wordcopy(word,saveword,length);
  reverse(word,length);
  
  if (equal(word,saveword,length))
    cout << "Your word is a palimdrome.\n";
  else
    cout << "Your word is NOT a palindrome.\n";
}

// Works similar to strcpy
void wordcopy(char word[], char saveword[], int length) {
 
  for (int i=0;i<length;i++)
    saveword[i] = word[i];
}

void reverse(char word[], int length) {

  for(int i=0;i<length/2;i++)
    swap(word[i],word[length-1-i]);
}

// A simplified version of strcmp
bool equal(char word[], char word2[], int length) {
  int i;
  for (i=0;i<length;i++) {
    if (word[i]!=word2[i])
      return false;
  }
  return true;
}

void swap(char &a, char &b) {
  char temp = a;
  a = b;
  b = temp;
}

Example #2
----------
#include <iostream.h>
#include <fstream.h>
void readmatrix(int a[][10], ifstream &matrix);
void addmatrix(int a[][10], int b[][10], int c[][10], int dim);
void transpose(int a[][10], int dim);
void printmatrix(int a[][10], int dim);
void swap(int &a, int &b);

void main() {

  ifstream file1, file2;
  int matrix1[10][10], matrix2[10][10], matrix3[10][10];
  // Read matrices from a file
  file1.open("m1.txt");
  file2.open("m2.txt");
  readmatrix(matrix1,file1);
  readmatrix(matrix2,file2);
  file1.close();
  file2.close();

  // Add the two matrices and transpose the sum matrix.
  addmatrix(matrix1,matrix2,matrix3,10);
  printmatrix(matrix3,10);
  cout << endl;
  transpose(matrix3,10);
  printmatrix(matrix3,10);
}

void addmatrix(int a[][10], int b[][10], int c[][10], int dim) {
  int i,j;
  for (i=0;i<dim;i++)
    for (j=0;j<dim;j++)
      c[i][j] = a[i][j]+b[i][j];
}

void transpose(int a[][10], int dim) {
  int i,j;
  for (i=0;i<dim;i++)
    for (j=i+1;j<dim;j++)
      swap(a[i][j],a[j][i]);
}

void printmatrix(int a[][10], int dim) {
  int i,j;
  for (i=0;i<dim;i++) {
    for (j=0;j<dim;j++)
      cout << a[i][j] << " ";
    cout << endl;
  }
}

void readmatrix(int a[][10], ifstream &matrix) {  
  int i,j;
  for (i=0;i<10;i++)
    for (j=0;j<10;j++)
      matrix >> a[i][j];
}

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