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Computer ProgramQbasic:
REM This program adds, subtracts and multiplies matrices
REM It uses no commands that are specific to matrices
CLS
DIM a(10,10)
DIM b(10,10)
DIM c(10,10)
PRINT “This program will add, subtract or multiply matrices whose”
PRINT “dimensions are less than 10. ”
PRINT
PRINT “Enter the dimensions of the first matrix”
INPUT “ separated by a comma. ”,m,n
REM This loop reads the first matrix
PRINT
PRINT “Please press enter after each element of the matrix. ”
PRINT “Enter all the elements of one row before the next row. ”
FOR i=1 to m
FOR j=1 to n
INPUT a(i,j)
NEXT j
NEXT i
100 REM This allows the user to choose what to do next.
PRINT
INPUT “Do you wish to 1)add 2) subtract 3) multiply or 4) end ”,s
IF s=4 THEN GOTO 500
200 PRINT
INPUT “Enter the dimensions of the next matrix. ”,m2,n2
REM The next statements check to make sure the dimensions are correct
REM for the operation
IF (((s=1 or s=2) AND (m<<>m2 OR n<>n2) OR (s=3 AND n<>n2)) THEN
PRINT “The matrix dimensions are not correct”
GOTO 200
END IF
PRINT
PRINT “Enter the next matrix. ”
FOR i=1 to m2
FOR j=1 to n2
INPUT b(i,j)
NEXT j
NEXT i
IF s=1 THEN GOSUB 1000 ELSE IF S=2 THEN GOSUB 2000 ELSE IF S=3
THEN GOSUB 3000 ELSE IF S=4 THEN GOTO ELSE GOTO 100
REM The previous line should be part of the one above it
PRINT
PRINT “The resulting matrix is: ”
FOR i=1 to m
FOR j=1 to n
PRINT a(i,j),
NEXT j
PRINT
NEXT i
PRINT
GOTO 100
500 PRINT
PRINT “Your final solution is: ”
FOR i=1 to m
FOR j=1 to n
PRINT a(i,j),
NEXT j
PRINT
NEXT i
END
1000 REM This adds matrices
FOR i=1 to m
FOR j=1 to n
a(i,j)=a(i,j) + b(i,j)
NEXT j
NEXT i
RETURN
2000 REM This subtracts matrices
FOR i=1 to m
FOR j=1 to n
a(i,j)=a(i,j) - b(i,j)
NEXT j
NEXT i
RETURN
3000 REM This multiplies matrices
FOR i=1 to m
FOR j=1 to n
c(i,j)= 0
FOR k=1 to n
c(i,j)=c(i,j) + a(i,k) $*$ b(k,j)
NEXT k
NEXT j
NEXT i
n=n2
FOR i=1 to m
FOR j=1 to n
a(i,j) = c(i,j)
NEXT j
NEXT i
RETURN
Pascal:
Program mult(input, output);
{This program adds, subtracts, and multiplies matrices.}
uses crt; {Necessary for some Pascal compilers}
type
matrix=array[1..10,1..10] of real;
var
choice : integer; {for choosing operation}
m,n,m2,n2 : integer; {dimensions of the matrices}
a,b,c : matrix; {matrix}
procedure readmatrix(var a:matrix; m,n:integer);
var
i,j: integer; {counters}
begin {read}
for i:=1 to m do
begin {do}
for j:=1 to n do
read(a[i,j]);
readln;
end {do}
end; {read}
procedure writematrix(a:matrix; m,n:integer);
var
i,j: integer; {counters}
begin {write}
for i:=1 to m do
begin {each line}
writeln;
for j:=1 to n do
write(a[i,j]:6:2);
end; {each line}
writeln;
end; {write}
procedure addmatrix(var a:matrix; b: matrix);
var
i,j: integer; {counters}
begin {addmatrix}
for i:=1 to m do
for j:=1 to n do
a[i,j]:=a[i,j]+b[i,j];
end;{addmatrix}
procedure submatrix(var a:matrix; b: matrix);
var
i,j: integer; {counters}
begin {submatrix}
for i:=1 to m do
for j:=1 to n do
a[i,j]:=a[i,j]-b[i,j];
end;{submatrix}
procedure multmatrix(var a:matrix; b:matrix; m:integer;
var n:integer; m2,n2:integer);
{The above row should be attached to the first row}
var
i,j,k: integer; {counters}
c: matrix; {temporary matrix}
begin {multmatrix}
for i:=1 to m do
for j:=1 to n2 do
begin {inner product}
c[i,j]:=0;
for k:=1 to n do
c[i,j]:=c[i,j]+a[i,k]*b[k,j];
end; {inner product}
n:=n2;
for i:=1 to m do
for j:=1 to n do a[i,j]:=c[i,j];
end;{multmatrix}
procedure menu{(var choice:char)};
begin {menu}
writeln;
writeln('Do you wish to :');
writeln(' 1. Add');
writeln(' 2. Subtract');
writeln(' 3. Multiply');
writeln(' 4. End the program');
readln(choice);
end;{menu}
procedure operation(var a : matrix);
begin {operation}
writeln('Enter the dimensions of the second matrix ');
writeln('separated by a space. Then hit return.');
read(m2,n2);
if (((m<>m2) or (n<>n2)) and ((choice=1) or (choice=2))) then
begin {if}
writeln('The dimensions are not correct for that operation.');
choice := 5;
end {if m}
else if ((choice = 3) and (m2 <> n)) then
begin {else if choice}
writeln('The dimensions are not correct for multiplication.');
choice := 5;
end{elseif choice}
else if ((choice<>1) and (choice<>2) and (choice<>3)
and (choice<>4)) then {this line should be attached
to the previous line}
begin {else if}
writeln('That was not a choice');
choice := 5;
end;{else if}
if (choice<>5) then
begin {if}
writeln('Enter your matrix.);
writeln('Enter the elements of each row separated');
writeln('by a space. Hit return at the end of each row.');
readmatrix(b,m2,n2);
end; {if}
if choice = 1 then
addmatrix(a,b)
else if choice = 2 then
submatrix(a,b)
else if choice = 3 then
multmatrix(a,b,m,n,m2,n2);
end;{operation}
begin{main program}
clrscr;
choice := 0;
writeln('Enter the dimensions of the first matrix ');
writeln('separated by a space. Then hit return.');
read(m,n);
writeln('Enter your matrix.);
writeln('Enter each element followed by a return.');
writeln('Enter the first row before you go to the next row.');
readmatrix(a,m,n);
menu;
while choice <> 4 do
begin {while}
operation(a);
writeln('The resulting matrix is :');
writematrix(a,m,n);
menu
end; {while}
writeln('The final resulting matrix is :');
writematrix(a,m,n);
writeln('Press return to leave the program');
readln;
end. {main program}
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Updated: September 22, 2000
Copyright ©1995 - 2000 Tamara Lynn Anthony
Notice that this is a column vector. 
the vector
and the scalar c = c.
,
so
