PROGRAM ROW_ADD

! This program adds each row of a matrix A and returns the result in an array B.

! All indices of A and B start at 1. The rth element of B will have the sum of

! the rth row of A.

IMPLICIT NONE

INTEGER :: M, N, I, K

REAL, DIMENSION(:,:), ALLOCATABLE :: A

REAL, DIMENSION(:), ALLOCATABLE :: B

! Now read number of rows and number of columns of A.

PRINT *, "Enter number of rows followed by number of columns:"

READ *, M, N

! Now allocate memory for matrix A and array B:

ALLOCATE(A(M,N))

ALLOCATE(B(M))

! Now read elements of A.

PRINT *, "Enter elements of A row by row:"

DO I=1, M

READ *, (A(I,K), K=1, N)

END DO

! Note you can implement the above DO loop using other ways. For example,

! you can replace the above by:

! READ *, ((A(I,K), K=1, N), I=1, M) .

! A similar thing can be said about all DO loops below.

!====================

!Finding the sum of each row of A starts here.

B=0 !You can remove this statement.

DO I=1, M

DO K=1, N

B(I)=B(I)+A(I,K)

END DO

END DO

!Finding the sum of each row of A ends here.

!====================

! Now we print A and then B:

PRINT *, "Matrix A is:"

DO I=1, M

PRINT *, (A(I,K), K=1, N)

END DO

PRINT *

PRINT *, "Sum of the rows:"

PRINT *, B

! You use DEALLOCATE and ALLOCATE only for run-time arrays.

DEALLOCATE(A, B)

END PROGRAM ROW_ADD