array of string

[yanyanhan]

Hi,

How to create an array of string from an input file? I was using the following cods and got error.

Ex:
Input file: suit.txt has 4 lines
hearts
diamonds
clubs
spades

code:
char *suitArr[4];
...
ifstream infile("suit.txt", ios::in);
...
for (int x=0; x < 4; x++)
{
infile.getline(inlineBuf,20);
char *suiteArr[x] = new char [strlen(inlineBuf) +1);
assert( suiteArr[x] !0 );
strcpy(suitArr[x],inlineBuf);
}

[Banfa]

And error at compile time or run time?
What was the exact error?
How is inlineBuf declared?

[Ashish_CPP]

Hi,
The following code can fetch 20 strings each of 19 characters at max from a Ex.txt file in C drive. Copy paste the code n it will work.

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

void main(void)
{
FILE *f;
char arr[20][20], i=0,j=0;
memset((char*)&arr[0][0], 0, 400);
f = fopen((const char*)"C:\\Ex.txt","r+");

for(i=0;i<20;i++)
{
for(j=0;j<20;j++)
{
arr[i][j] = fgetc(f);
if(arr[i][j]==10)
{
arr[i][j] = '\0';
break;
}
else if(arr[i][j]==(-1))
{
arr[i][j] = '\0';
break;
}
}
}
printf("%s\n\n",&arr[2][0]);
}

[Banfa]

When posting code if you put it in

 ... 

then indentation will be preserved.

The casts in the following 2 statements are not required and it is probably better to leave them out.

memset((char*)&arr[0][0], 0, 400);
f = fopen((const char*)"C:\\Ex.txt","r+");


This line of code is open to error

arr[i][j] = fgetc(f);

the prototype of fgetc is

int fgetc( FILE *stream );

but you have imediately assigned it to char demoting it's type. You have no garunttee that EOF will fit in a char (especially if char is unsigned on the platform in question). To ensure correct operation and portability you should assign the return of fgetc to a int variable, check it against EOF and if it is not EOF then you should assign it to a char (if required).

This line is checking for EOF

else if(arr[i][j]==(-1))

you have no garunttee for any given platform that EOF is -1. You should use the defined symbol EOF as this is correct for all platforms.

[Ashish_CPP]

Yes I agree with you Bafna. But I have struggled with this EOF manytimes becoz it doesn't work manytimes.

[Banfa]

corrected

#include <stdio.h>
#include <stdlib.h>
 
void main(void)
{
    FILE *f;
    int input;
    char arr[20][20], i=0,j=0;
    memset((char*)&arr[0][0], 0, 400);
    f = fopen((const char*)"C:\\Ex.txt","r+");
 
    for(i=0;i<20;i++)
    {
        for(j=0;j<20;j++)
        {
            input = fgetc(f);
 
            if(input=='\r')
            {
                arr[i][j] = '\0';
                break;
            }
            else if(input==EOF)
            {
                arr[i][j] = '\0';
                break;
            }
            else 
            {
                arr[i][j] = input;        
            }
        }
    }
    printf("%s\n\n",&arr[2][0]);
}

[Banfa]

Yes I agree with you Bafna. But I have struggled with this EOF manytimes becoz it doesn't work manytimes.

If you are assing fgetc to a char then it is probably a sign/demotion issue.

[Ashish_CPP]

Thanks Bafna. I think fgetc() is used to fetch values from a file and no character/value can exceed the limit of -128 to +127 so return value of fgetc can always be transferred to a char variable without loss. I am not sure but I think so.