arrays_lesson5.cpp

//Notes-1:

/*
C++ arrays can be declared as:

variableType arrayName [ ] = {variables to be stored in the array};

or as:

variableType arrayName[array size] 
*/

//Notes-2:

/* 
We can access the values in an array by identifying the specific index.

variableType arrayName[ index number ]
*/


//Example
 /*Goal: Practice array manipulation in C++. 
 **The user will input 40 integers. 
 **Put them into an array. Then print the array in the order the numbers were
 **entered. Then print in reverse order. Then sort the array in ascending order 
 **and print it. 
 */

 #include <iostream>
 #include <stdio.h>

 int main()
 {
     int userInput[40];

     //Enter the numbers into an array called userInput
     for(int i = 0; i < 40; i++)
     {
         scanf("%d", &userInput[i]);
     }
     //print the array
     std::cout<<"\nThe array\n";
     for(int i = 0; i < 40; i++)
     {
         std::cout << userInput[i] <<" ";
     }
     //print the array in reverse order
     std::cout<<"\n\nThe array in reverse order\n";
     for(int i = 39; i >= 0; i--)
     {
         std::cout << userInput[i] <<" ";
     }    
     //sorting the array
      for(int i = 0; i < 40; i++)
     {
         for(int j = 0; j < 39 - i; j++)
             {
                 if(userInput[j] > userInput[j + 1])
                 {
                     int temp;
                     temp=userInput[j];
                     userInput[j]=userInput[j + 1];
                     userInput[j + 1]=temp;
                 }
             }
     }
std::cout<<"\n\nThe array sorted\n";
    for(int i = 0; i< 40; i++)
{
    std::cout << userInput[i] <<" ";
}
return 0;
 }

//Example-2: 
/*Goal: practice searching an array in C++
 **There is an array of integers. The length of the arrays to be searched 
 **varies. A user will enter a postive integer and the program will search the array.
 **If the value is in the array, the program will return the location of 
 **the element. If the value is not in the array, the user will be notified 
 **that the value is not in the array. To exit the program the user will enter -1.
 */

 #include <iostream>
 #include <stdio.h>

 int main()
 {
     int searchKey = 0;
     int searchArray[10] = {324,4567,6789,5421345,7,65,8965,12,342,485};
     int location = 0;

     while(1)
     {
         std::cout<<"Enter an integer ('-1' to quit): ";
         scanf("%d", &searchKey);
         std::cout<< searchKey<<"\n";
         if(searchKey == -1)
         {
             break;
         }
         for(int i = 0; i < 10; i++)
         {
             if(searchKey == searchArray[i])
             {
                 location = i;
                 break;
             }
             location = -1;
         }
         if(location != -1)
         {
             std::cout<<searchKey<<" is at location "<<location<<" in the array.\n";
         }
         else
         {
             std::cout<<searchKey<<" is not in the array.\n";
         }
    }
     return 0;
 }

//Note-3: How to create multi-array: 

/*Goal: understand multidimensional arrays in C++*/

#include<iostream>

int main()
{
    int array2Dim[2][3] = {0,1,2,3,4,5};
    for(int i=0; i<2;i++)
        for(int j=0;j<3;j++)
            std::cout<<"array2Dim["<<i<<"]["<<j<<"] = " << array2Dim[i][j]<<"\n";
    return 0;
}