Sum elements column by column Program Code:

# Function to calculate the sum of elements in a specified column of a matrix
def sumColumn(m, columnIndex):
    total = 0
    for row in m:
        total += row[columnIndex]
    return total

# Test program
def main():
    matrix = []  # Initialize an empty matrix

    # Prompt the user to enter a 3x4 matrix
    for i in range(3):
        row = input(f"Enter a 3-by-4 matrix row for row {i}: ").split()
        row = [float(num) for num in row]  # Convert the input numbers to floats
        matrix.append(row)

    # Display the sum of each column
    for j in range(4):
        columnSum = sumColumn(matrix, j)
        print(f"Sum of the elements for column {j} is {columnSum}")

# Call the test program
main()

Executed Output:

Enter a 3-by-4 matrix row for row 0: 1.5 2 3 4
Enter a 3-by-4 matrix row for row 1: 5.5 6 7 8
Enter a 3-by-4 matrix row for row 2: 9.5 1 3 1

Sum of the elements for column 0 is 16.5
Sum of the elements for column 1 is 9.0
Sum of the elements for column 2 is 13.0
Sum of the elements for column 3 is 13.0