1. Introduction to Programming
Lecture # 17
Air University

2. Matrix
Rows
Columns

3. Matrix 1 9 8 7 6 5 4 3 2 1
Row 1
Row 2
Row 3 9 8 7 6 5 4 3 2 1
Row 1
Row 2
Row 3
Memory 3 2 1 6 5 4 9 8 7
Row 1
Row 2
Row 3
Output

4. x [rowIndex ] [ columnIndex ]
Two Dimensional Array
Need 2 loop to controll a matrix
int x [ i ] [j ] ;
x [rowIndex ] [ columnIndex ]

5. Multiple-Subscripted Arrays
Multiple subscripts
a[ i ][ j ]
Tables with rows and columns
Specify row, then column
“Array of arrays”
a[0][0] is the first element of that array
Row 0
Row 1
Row 2
Column 0
Column 1
Column 2
Column 3
a[ 0 ][ 0 ]
a[ 1 ][ 0 ]
a[ 2 ][ 0 ]
a[ 0 ][ 1 ]
a[ 1 ][ 1 ]
a[ 2 ][ 1 ]
a[ 0 ][ 2 ]
a[ 1 ][ 2 ]
a[ 2 ][ 2 ]
a[ 0 ][ 3 ]
a[ 1 ][ 3 ]
a[ 2 ][ 3 ]
Column subscript
Array name
Row subscript

6. Multiple-Subscripted Arrays
To initialize
Initializers grouped by row in braces
int b[ 2 ][ 2 ] = { { 1, 2 }, { 3, 4 } };
int b[ 2 ][ 2 ] = { { 1 }, { 3, 4 } };
1 2
3 4
Row 0
Row 1
1 0
3 4

7. Multiple-Subscripted Arrays
Referenced like normal
cout << b[ 0 ][ 1 ];
Outputs 0
Cannot reference using commas
cout << b[ 0, 1 ];
Syntax error
Function prototypes
Must specify sizes of subscripts
First subscript not necessary, as with single-scripted arrays
void printArray( int [][ 3 ] );
1 0
3 4

8. 2 D Array E.g int maxRows = 2; int maxCols = 3 ;
int matrix [ 2] [ 3 ]; int row , col ;
for ( row = 0 ; row < maxRows ; row ++ ) {
for ( col = 0 ; col < maxCols ; col ++ )
cout << “Please enter value of ”<< row << “ “ << col;
cin >> matrix [ row ] [ col ] ; }

9. After second outer loop
2 D Array E.g
After first outer loop
Input
[0] 5 2 9
After second outer loop
Input
[0] 5 2 9 7 4
[1]

10. Three Dimensional Arrays
int x [ ] [ ] [ ] ;

11. 2 D Array (Addition) Write a program in C++ that take two matrices
and then Add them After inserting two matrices
first display the both matrices and then add
them and show the result. i.e

12. 2 D Array (Addition) Matrix 1 Matrix 2 1 2 3 1 2 3 4 5 6 4 5 6
Result = Matrix 1 + Matrix2
2 4 6

13. 2 D Array (Addition) (code)
#include<iostream.h>
# define size 3
int main () //Starts Main {
int ar1[size][size],ar2[size][size],
ar3[size][size];

14. 2 D Array (Addition) (code)
cout<<"***Enter First Matrics*** \n";
for(int a=0; a<size; a++) {
for(int a1=0; a1<size; a1++)
cout<<"First Matrics ElementNo.["<<a<<":"<<a1<<"]=";
cin>>ar1[a][a1]; }

15. 2 D Array (Addition) (code)
cout<<"***Enter Second Matrics***\n";
for(int b=0; b<size; b++) {
for(int b1=0; b1<size; b1++)
cout<<"Second Matrics Element No.["<<b<<":"<<b1<<"]=";
cin>>ar2[b][b1]; }

16. 2 D Array (Addition) (code)
//DISPLAY OF FIRST MATRICS
cout<<"\n***You Entered First Matrics***";
for (int a2=0; a2<size; a2++) {
cout<<"\n";
for (int a3=0; a3<size; a3++)
cout<<ar1[a2][a3]<<"\t"; }

17. 2 D Array (Addition) (code)
//DISPLAY OF SECOND MATRICS
cout<<"\n***You Entered Second Matrics***";
for (int b2=0; b2<size; b2++) {
cout<<"\n";
for (int b3=0; b3<size; b3++)
cout<<ar2[b2][b3]<<"\t"; }
cout<<endl;

18. 2 D Array (Addition) (code)
//Adding two Matrices
for (int d=0; d<size; d++) {
for (int d1=0; d1<size; d1++)
ar3[d][d1] = ar1[d][d1] + ar2[d][d1]; }

19. 2 D Array (Addition) (code)
//RESULT OUTPUT
cout<<"\nThe Result Of Two Matrices is as Follow\n";
for(int c=0; c<size; c++) {
cout<<"\n";
for (int c1=0; c1<size; c1++)
cout<<ar3[c][c1]<<"\t"; }
} cout<<endl;return 0; }

20. Enter the values in a matrix and print it in reverse Column order
More Exercise
Enter the values in a matrix and print it in reverse Column order 9 8 7 6 5 4 3 2 1
[0] [1] [2] 7 8 9 4 5 6 1 2 3
[2] [1] [0]

21. Transpose E.g 1 2 3 4 5 6 7 8 9

22. Transpose E.g Write a Program in C++ that Display
the Transpose of Matrix.
Matrix 1 Transpose

23. Transpose E.g (code) #include<iostream.h> # define size 3
int main () // Starts Main {
int ar2[size][size],ar2t[size][size];

24. Transpose E.g (code) cout<<"***Enter The Matrics***\n";
for(int b=0; b<size; b++) {
for(int b1=0; b1<size; b1++)
cout<<" Matrics Element No.["<<b<<":"<<b1<<"]=";
cin>>ar2[b][b1]; }

25. Transpose E.g (code) //DISPLAY OF MATRICS
cout<<"\n***You Entered Matrics***";
for (int b2=0; b2<size; b2++) {
cout<<"\n";
for (int b3=0; b3<size; b3++)
cout<<ar2[b2][b3]<<"\t"; }

26. Transpose E.g (code) //TRANSPOSE OF MATRICS
cout<<"\n***The Transpose Of Matrics Is as Follow***\n";
for(int x=0; x<size; x++) {
for (int x1=0; x1<size; x1++)
ar2t[x][x1] = ar2[x1][x]; }

27. Transpose E.g (code) // DISPLAY OF TRANSPOSE OF MATRICS
for( int y=0; y<size; y++) {
cout<<"\n";
for(int y1=0; y1<size; y1++)
cout<<ar2t[y][y1]<<"\t"; }
cout<<endl;
return 0;

28. 2 D Array (Sale)
A Distributor of a Pharmaceutical Company has 4 Districts, for supply the medicine. He requires a program that can display the sales of all his Districts. Write a Program in C++ Using two Dimensional Array that shows the Following Out put. The Program should display the Sale, Districts wise and up to 3 Months i.e
Month1 Month2 Month3
Sale of Districts # 1 =
Sale of Districts # 2 =
Sale of Districts # 3 =
Sale of Districts # 4 =

29. 2 D Array (Sale) (code) #include<iostream.h> int main() {
const int districts=4;
const int months=3;
int d,m;
double sales[districts][months];

30. 2 D Array (Sale) (code) //Taking Sale of three Months District Wise
for(d=0; d<districts; d++) {
for(m=0; m<months; m++)
cout<<"Enter The Sales Of District="<<d+1<<" ";
cout<<",Month"<<m+1<<"=";
cin>>sales[d][m]; }

31. 2 D Array (Sale) (code) //Displaying the Sale District Wise
cout<<"\n\n\n";
cout<<"\n\nThe Sale Of Districts Is \n";
for(d=0; d<districts; d++) {
cout<<"\n District # "<<d+1<<" sales :";
for(m=0; m<months; m++)
cout<<sales[d][m]<<"\t"; }
cout<<endl;
return 0;

32. OutPut Enter The Sales Of District=1 ,Month1=100
The Sale Of Districts Is
District # 1 sales :
District # 2 sales :
District # 3 sales :
District # 4 sales :
Press any key to continue

33. Agent Program Write a program in C++, which take Agent
code (123,258,..) and traveling expense
(Rs = 5000, 6000,…) of the agent. Find the
agent who had spent most money in all, Display
the agent code and amount after searching in 2
D Array.

34. Agent Program Out put Enter 3 digit agent number = 123
then enter traveling expenses Rs=5000
Enter 0 0 to quit
Enter agent number & Expense =
Enter agent number & Expense =
Enter agent number & Expense =
Enter agent number & Expense =
Enter agent number & Expense =0 0
Agents with higest Expense :
Agent Code = 963
Amount = 65478
Press any key to continue

35. Agent Program(CODE) #include<iostream.h> #define ROWS 10
#define COLUMNS 2
int maxex (int [][COLUMNS], int );
void main () {
int agents[ROWS][COLUMNS];
int number,expenses;
int index = 0;
cout<<"\nEnter 3 digit agent number = 123\n"
<<"then enter traveling expenses Rs=5000 \nEnter 0 0 to quit\n";

36. Agent Program(CODE) do {
cout<<"\nEnter agent number & Expense =";
cin>>number>>expenses;
agents[index][0] = number;
agents[index][1] = expenses; }
while(agents[index++][0] !=0.0);
index--;
index= maxex(agents,index);
cout<<"\nAgents with higest Expense :\nAgent Code = "<<agents[index][0];
cout<<"\nAmount = "<<agents[index][1]<<endl;

37. Agent Program(CODE) int maxex (int list[][COLUMNS], int size) {
int dex,maxdex;
int max;
max = list[0][1];
maxdex = 0;
for(dex=1; dex<size; dex++)
if(max < list[dex][1])
max = list[dex][1];
maxdex = dex; }
return (maxdex);