RE: [Dev-C++] how to use strings

[Johannes P. <joh...@pr...>]

Okay
Problem 2 is actually kinda simple in the sense if I understand you correctly

//SNIP

#include <stdio.h>
#include <alloc.h>

main(int argc, char *argv[]) {
    FILE *CheckFile;
    int Byte;
    unsigned int Checksum;
    int read=-1;
    int filePos =0;

    if ( argc != 2 ) {
       printf("usage: checksum filename\n");
       exit(1);
    }

    if ( (CheckFile = fopen(argv[1], "rb")) == NULL ) {
       printf("Can't open file: %s\n", argv[1]);
       exit(1);
    }

    /* Initialize the checksum accumulator */
    Checksum = 0;

  fseek (CheckFile, 0L, SEEK_SET);

     char c1[100];
     char c2[100];
     char c3[100];
     char c4[100];
     char c5[100];

     memset(c1,0,100);
     memset(c2,0,100);
     memset(c3,0,100);
     memset(c4,0,100);
     memset(c5,0,100);
     printf ("pos %d\n", ftell (CheckFile));
     printf("Succesfull assignments : %d c1 : %s\n c2 : %s\n",fscanf 
(CheckFile, "%s%s%*[\n]", c1, c2),c1,c2);

      //part 1
      printf("Succesfull assignments : %d c3 : %s\n c4 : %s\n c5 : %s 
",fscanf (CheckFile, "%*[^'O]%s%s%s", c3, c4, c5),c3,c4,c5);
      //part 2
      //printf("Succesfull assignments : %d c3 : %s\n c4 : %s\n c5 : %s 
",fscanf (CheckFile, "%s%s%s%*[\n]", c3, c4, c5),c3,c4,c5);
     printf ("pos %d\n", ftell (CheckFile));
    fclose(CheckFile);
    exit(0);
}

//END SNIP

If you take the above code and run it it does the same as your application.
If you comment part 1 out and uncomment part 2 it reads the next line as 
needed. The reason is that you have told the function to move the
cursor until it reaches one of the specified characeters in part 1 that is 
a qute (') or a captial O. This is why it runs until past that point as one 
of there charcters only
comes after that to test. Enter a capital O in the second line of the program.

Well this is all I can think of now. One thing thou using %s to read a 
string into a char array is DANGEROUS for the function will read the string 
into it regardless of its size.
To test put in a string in the first line that is MORE than 100 then printf 
(well I geuss my program can also be wrong)

if you rather use a char pointer you can read in more that the 100 
specified. yust remmeber the free.. here is a code sample to replace in the 
above.

//SNIP 2
     char *c1;
     char c2[100];
     char c3[100];
     char c4[100];
     char c5[100];

//    memset(c1,0,100);
     memset(c2,0,100);
     memset(c3,0,100);
     memset(c4,0,100);
     memset(c5,0,100);
     printf ("pos %d\n", ftell (CheckFile));
     printf("Succesfull assignments : %d c1 : %s\n c2 : %s\n",fscanf 
(CheckFile, "%s%s", c1, c2),c1,c2);
     free(c1);
//END SNIP 2

Well good luck
Johannes