fgetc not displaying correctly after space - c

Question

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main() {
FILE *userfile, *pwfile, *usernamesPasswords, *readUsernamesPasswords;
char u, p, user[20][25], pass[20][20], userLine[25], passLine[20];
int i = 0;
int j = 0;
int userIndex = 0;
int passIndex = 0;
userfile = fopen("usernames.txt", "r");
pwfile = fopen("passwords.txt", "r");
if (userfile == NULL || pwfile == NULL) {
printf("Cannot open file \n");
exit(0);
}
u = fgetc(userfile);
while (u != EOF) {
if ( u != '\n'){
userLine[userIndex++] = u;
} else {
userLine[userIndex] = '\0';
strcpy(user[i], userLine);
userIndex = 0;
i++;
}
u = fgetc(userfile);
}
fclose(userfile);
p = fgetc(pwfile);
while (p != EOF) {
if ( p != '\n'){
passLine[passIndex++] = p;
} else {
passLine[passIndex] = '\0';
strcpy(pass[j], passLine);
passIndex = 0;
j++;
}
p = fgetc(pwfile);
}
fclose(pwfile);
usernamesPasswords = fopen("usernamesPasswords.txt", "w");
int w, k;
char newLine[1024];
for (w=0;w<20;w++) {
strcat(newLine, user[w]);
int q = strlen(newLine);
for (k=0;k<(25-q);k++) {
strcat(newLine, " ");
}
strcat(newLine, pass[w]);
strcat(newLine, "\n");
strcat(newLine, "\0");
fputs(newLine ,usernamesPasswords);
strcpy(newLine, "");
}
fclose(usernamesPasswords);
printf("\nDo you want to display the new file? Enter (y) to view and any other key to exit\n");
char word;
scanf("%c",&word);
if (word == 'y') {
readUsernamesPasswords = fopen("usernamesPasswords.txt", "r");
if (readUsernamesPasswords == NULL) {
printf("Cannot open file \n");
exit(0);
}
char r;
while((r=fgetc(readUsernamesPasswords))!=EOF) {
printf("%c", r);
}
fclose(readUsernamesPasswords);
}
return 0;
}
Expected Output:
Moodie 123456
Intelllligent password
Happee 12345678
Mischeivous qwerty
SweetKristy 123456789
KristyHoney 12345
BubblySnowflake 1234
AngelicPrincessKristy 111111
FairyPrincessKristy 1234567
BabyKristyButterfly dragon
daffyusers 123123
magpiedoodle baseball
aspiringthreat abc123
landmarksspreader football
cavaliervanquish monkey
chatteringparma letmein
veggiehydrogen 696969
teethunsure shadow
rumpboast master
lidarstrudel 666666
Instead...
123456
password
12345678
qwerty
123456789
12345
1234ke
111111incessKristy
1234567sKristy
dragonutterfly
123123
baseball
abc123
footballer
monkeysh
letmein
696969
shadow
master
666666
This only happens when I try to output on terminal.
The actual usernamesPasswords.txt file comes out as expected.
The left side of strings only seem to get printed only when I newline in place of whitespace...
I even tried fgets and fread but similar output. I have read other posts about eating or consuming so I tried using fgets or fread as suggested and even tried unget. did not seem to work. I have been looking all over stack overflow to no avail.
If this is a duplicate, I apologize in advanced. I have really tried to look all over the web for couple hours before deciding to post.
I usually don't post cuz stack overflow usually has everything already...
Please help! Thank you!

Answer 1

You cannot call strcat or strlen on uninitialized storage. It's Undefined Behaviour. String functions generally require input string arguments to be correctly NUL-terminated. (Without the terminator, there is no way to tell where the string ends.)
And strcat(s, "\0") is a no-op because the second argument is effectively an empty (zero-length) string. (And, as above, if s is not already NUL-terminated, it is Undefined Behaviour.)

Answer 2

In your program, this part of code is having few problems:
char newLine[1024];
for (w=0;w<20;w++) {
strcat(newLine, user[w]);
int q = strlen(newLine);
for (k=0;k<(25-q);k++) {
strcat(newLine, " ");
}
strcat(newLine, pass[w]);
strcat(newLine, "\n");
strcat(newLine, "\0");
fputs(newLine ,usernamesPasswords);
strcpy(newLine, "");
}
Problems like newLine buffer is not initialized and used in strcat. Concatenating empty string has no effect - strcat(newLine, "\0");. You can solve these problems by simply initializing buffer with {0} and instead of concatenating an empty string, assign \0 at appropriate buffer index. But you don't need to do all this strcat's, instead you can simply do all this in just one line like this:
char newLine[1024];
for (w=0;w<20;w++) {
snprintf (newLine, 1024, "%-25s%s\n", user[w], pass[w]);
fputs(newLine ,usernamesPasswords);
}
snprintf appends a terminating null character after the content written to the buffer.
Few points:
- You should check the return value of fopen.
- The return type of fgetc is int and not char and you are taking its return value in a char type.
- You need to take care of few things in your program like your program works on an assumption that usernames.txt and passwords.txt contains exact 20 lines. It's better to make it flexible.