不要使用strtok。第九层地狱包含3个功能：gets、scanf和strtok。请避免使用它们。使用fgets读取数据，然后使用strtol系列中的某个元素解析它。例如：

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

#define ROW 5
#define COL 4

static void
die(int row, int col)
{
    fprintf(stderr, "Invalid input in row %d, near column %d\n", row, col);
    exit(1);
}

int
main(int argc, char **argv)
{
    const char *path = argc > 1 ? argv[1] : "matrix-samples/m-5-10-a.txt";
    int matrix[ROW][COL];
    FILE *ifp = fopen(path, "r");
    char str[256];
    if( ifp == NULL ){
        perror(path);
        return EXIT_FAILURE;
    }
    int row = 0;
    while( row < ROW && fgets(str, sizeof str, ifp ) != NULL ){
        char *p = str;
        for( int col = 0; *p && col < COL; col += 1 ){
            char *end;
            matrix[row][col] = strtol(p, &end, 10);
            if( ! isspace(*end) ){
                die(row, end - str);
            }
            p = end + 1;
        }
        while( isspace(*p) ){
            p += 1;
        }
        if( *p || p[-1] != '\n' ){
            die(row, p - str);
        }
        row += 1;
    }
    if( fgetc(ifp) != EOF ){
        die(row, 0);
    }
    for( int i = 0; i < ROW; i++ ){
        for( int j = 0; j < COL; j++ ){
            printf("%7d", matrix[i][j]);
        }
        putchar('\n');
    }

    return 0;
}