Find and print a candidate in the sudoku.
str = sudoku_candidateprint ( X , C , L , d )
a 9-by-9 matrix, with 0 for unknown entries
a 9 x 9 cell of candidates
the 9 x 9 matrix of number candidates
the digit to find in the sudoku
the rows where the candidate is found
the columns where the candidate is found
Search for the candidate d in all the nonfixed cells of the sudoku X. The search is performed by sudoku_candidatefind. Then print the cells where the candidate d appears.