Question

Exercises on Arrays –using C++programming

1. You want an array with the numbers 100 – 105. In the boxes below, fill in what your array should have. Fill in the index of each element below it.

Array
Index

Open up your editor and write the following program:

Declare an array that has the numbers 100 to 105. (How many elements are there in the array?) Print the array. Save your file and test it. Compare your results with your table above.

2. You want an array of 50 elements filled with the number 1. In the boxes below, fill in the first 8 elements of your array. Fill in the index of each element below it.

Array
Index

Create a program that creates this array in the main() function.

Create a program that adds the value of each previous array element to the current array element value; your program should start with a function called initArray() that initializes the array as above. Your program should output the array index, array element value, the previous array element value, and the new element value.

3. Create an array of months, fill it with the names of the months. Create a second array and fill it with the numbers 1-12. Create a third array and fill it with the number of days in each month. Write a short program that outputs in a logical way the number of days in each month. Create a function that tells you the number of days in any month. Test with February and in July.  Total the number of days at the end of each month (e.g. your program should say: on Jan. 31, there have been 31 days. On February 28, there have been 59 days)

months
numbers
days
index

Answer 1

[1]---------------------------------------------

Array	100	101	102	103	104	105
Index	0	1	2	3	4	5

#include <iostream>
using namespace std;
int main()
{
// Initializig an array
int i,a[] = {100,101,102,103,104,105};

// traversing through array
for(i=0;a[i];i++)
cout << a[i] << " ";
cout << endl << "Count : "<< i << endl;
  
return 0;
}

/* Sample output
100 101 102 103 104 105
Count : 6

*/

// Program printed, and expected are same

[2]---------------------------------------------

Array	1	1	1	1	1	1	1	1	1
Index	0	1	2	3	4	5	6	7	8

// Create a program that creates this array in the main() function.
#include <iostream>
using namespace std;
int main()
{
int a[50] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
return 0;
}

// Create a program that adds the value of each previous array element to the current array element value
#include <iostream>
using namespace std;

void initArray()
{
int i, prev,a[50] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
for(i=1;i<20;i++)
{
prev = a[i]; // storing existing element
a[i] = a[i] + a[i-1]; // adding previous element to it
  
// printing output
cout << i << "-"<< prev<< "-" << a[i+1]<< "-" << a[i] << endl;
}
}

int main()
{
initArray();
return 0;
}

/* Sample output
1-1-1-2
2-1-1-3
3-1-1-4
4-1-1-5
5-1-1-6
6-1-1-7
7-1-1-8
8-1-1-9
9-1-1-10   
10-1-1-11
11-1-1-12
12-1-1-13
13-1-1-14
14-1-1-15
15-1-1-16
16-1-1-17
17-1-1-18
18-1-1-19
19-1-1-20
21-1-1-22
22-1-1-23
23-1-1-24
24-1-1-25
25-1-1-26
26-1-1-27
27-1-1-28
28-1-1-29
29-1-1-30
30-1-1-31
31-1-1-32
32-1-1-33
33-1-1-34
34-1-1-35
35-1-1-36
36-1-1-37
37-1-1-38
38-1-1-39
39-1-1-40
40-1-1-41
41-1-1-42
42-1-1-43
43-1-1-44
44-1-1-45
45-1-1-46
46-1-1-47
47-1-1-48
48-1-1-49
49-1-1-50
*/

[3]---------------------------------------------

Months	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Numbers	1	2	3	4	5	6	7	8	9	10	11	12
Days	31	28	31	30	31	30	31	31	30	31	30	31
Index	0	1	2	3	4	5	6	7	8	9	10	11

#include <iostream>
#include <cstring>
using namespace std;

// finds the number of days for given month
void info(int d[])
{
int i, sum = 0,x;
cout << "Enter month to find out number of days[2-Feb,7-Jul] : ";
cin >> x;
cout << d[x-1] << endl;
}

int main()
{
// initializing arrays
string months[12] = {"Jan","Feb", "Mar", "Apr","May","Jun", "Jul","Aug","Sep","Oct","Nov","Dec"};
int a[12]={1,2,3,4,5,6,7,8,9,10,11,12};
int days[12]={31,28,31,30,31,30,31,31,30,31,30,31};
int sum = 0,i;

// calling to check twice
info(days);
info(days);

// looping for 12 times
for(i=0;i<12;i++)
{
sum+=days[i]; // adding the number of days
cout <<"On "<<months[i] <<" " << days[i] << ", there have been " << sum << " days" << endl;
}
return 0;
}

/* Sample run
Enter month to find out number of days[2-Feb,7-Jul] : 2
28   
Enter month to find out number of days[2-Feb,7-Jul] : 7
31
On Jan 31, there have been 31 days   
On Feb 28, there have been 59 days   
On Mar 31, there have been 90 days   
On Apr 30, there have been 120 days
On May 31, there have been 151 days
On Jun 30, there have been 181 days
On Jul 31, there have been 212 days
On Aug 31, there have been 243 days
On Sep 30, there have been 273 days
On Oct 31, there have been 304 days
On Nov 30, there have been 334 days
On Dec 31, there have been 365 days
*/