I am trying to validate a password in C, and one of my else statements is firing automatically whenever the code runs. I run a test to see if a character is a symbol, and if it is add 1 to int symbol using symbol++;, but the problem is that this code is executing regardless of whether the character I am testing is a symbol.
I think this issue has something to do with the structure of my if, else statements, and I have tried several combinations, but something is wrong that is throwing the program off I've used else if but that didn't help. This seems like it should be really obvious, but I can't seem to figure out what's wrong.
char password[30];
int lower, upper, number, symbol, i;
lower = upper = number = symbol = 0;
printf("Enter your password: ");
scanf("%s", &password);
int len = strlen(password);
for (i = 0; i <= len; i++) {
if (isalpha(password[i])){
if (isupper(password[i])){
upper++;
}
else{
lower++;
}
}
if (isdigit(password[i])){
number++;
}
else{
symbol++;
}
}
if (upper >= 1 && lower >= 1 && number >= 1 && symbol >= 1 && len >=6){
printf("Your password is good!");
}
if (upper < 1){
printf("You need an uppercase letter \n");
}
if (lower < 1){
printf("You need a lowercase letter \n");
}
if (number < 1){
printf("You need a number \n");
}
if (symbol < 1){
printf("You need a symbol \n");
}
if (len < 6){
printf("Your password must be at least 6 characters \n");
}
In your code, change
for (i = 0; i <= len; i++)
to
for (i = 0; i < len; i++)
as, C arrays have 0 based index. Otherwise, you may be overrunning allocated memory which in turn invokes undefined behaviour.
Note: Even if you don't overrun memory (as you have a compile time allocated array and the input maybe less than the actual array size), you'll end up comparing the terminating nul, which probably you don't want.
Then , the isdigit() check should not a standalone if (as per your logic), it should be an else if with isalpha().
That said,
scanf("%s", &password);
should be
scanf("%29s", &password);
to avoid any possible risk of buffer overflow.