add input values from arg in c into array for Sudoku solver

Question

I'm new to C and programming as a whole. I've got the basics down for a program I'm trying to get a better grasp of C, but I'm having trouble taking input from the users args at the command line to populate my array:

./sudoku.c "9...7...." "2...9..53" etc etc

I've tested my program using an array that I filled in and it works but that is no good if I can't take user input. My input looks something like this:

grid[9][9] = {{9, 0, 0, 0, 7, 0, 0, 0, 0},
              {2, 0, 0, 0, 9, 0, 0, 5, 3}};

Any suggestions?

Any help would be greatly appreciated

Answer 1

Just read with simple loops.

#include <stdio.h>
#include <string.h>
#include <ctype.h>

int main(int argc, char* argv[]) {
    int grid[9][9];
    int input_error = 0;
    int i, j;
    if (argc != 1 + 9) { /* check number of rows in input */
        input_error = 1;
    } else {
        for (i = 0; i < 9; i++) { /* read each rows */
            if (strlen(argv[i + 1]) != 9) { /* check number of cols in input */
                input_error = 1;
                break;
            }
            for (j = 0; j < 9; j++) { /* read each cols */
                if (isdigit(argv[i + 1][j]) && argv[i + 1][j] != '0') {
                    /* digits except for 0 */
                    grid[i][j] = argv[i + 1][j] - '0'; /* convert digit to integer */
                } else if (argv[i + 1][j] == '.') {
                    /* dot */
                    grid[i][j] = 0;
                } else {
                    /* invalid character */
                    input_error = 1;
                    break;
                }
            }
        }
    }
    /* check if some errors are detected */
    if (input_error) {
        fputs("invalid usage\n", stderr);
        return 1;
    }

    /* print what is read for testing */
    for (i = 0; i < 9; i++) {
        for(j = 0; j < 9; j++) {
            printf(" %d", grid[i][j]);
        }
        putchar('\n');
    }
    return 0;
}

Answer 2

Consider using text file as an input, and give filename as command line argument.

Example:

 #include <stdio.h> #include <ctype.h> int main(int argc, char* argv[]) { int lineCnt; int posCnt; FILE* inpFile = NULL; // check argument and file if( argc < 2 ) { printf("run program with argument - name of file\\n"); return 1; } inpFile = fopen(argv[1], "r"); if( inpFile == NULL ) { printf("file %s cannot be open\\n", argv[1]); return 2; } // reading from file int grid[9][9] = {0}; int chr; for( lineCnt = 0; lineCnt < 9; lineCnt++) { for ( posCnt = 0; posCnt < 9; posCnt++) { // read next not sapce character from file do{ chr = getc(inpFile); } while( isspace(chr) ); // check character if( chr == EOF ) // file is finished but array is not filled { printf("file %s if incomplete\\n", argv[1]); return 3; } if(chr == '.') // if(chr == '.' || chr == '0') { grid[lineCnt][posCnt] = 0; } else if(chr > '0' && chr <= '9') { grid[lineCnt][posCnt] = chr - '0'; } else { printf("file %s has incorrect format\\n", argv[1]); return 4; } } } // test output of input data for( lineCnt = 0; lineCnt < 9; lineCnt++) { for ( posCnt = 0; posCnt < 9; posCnt++) { printf("%i ", grid[lineCnt][posCnt]); } printf("\\n"); } } 

If you compine this example and run as

./sudoku.c sudoku1.txt

where sudoku1.txt is like

1...5.7..
...3.5.91
.5.6.7.87
11111....
....2222.
6.6.6.6.6
.1.1.1.1.
1.1.1.1.1
.9.9.9.99

you will understand my idea