Exception Being Thrown When Accessing Struct Array - c

Question

When I call the test() function, it prompts me to enter the bet for the first player in my struct array. It accepts my entry. On the second round in my for loop, when asking for the bet for the second person in my struct array, an exception is thrown after a value is entered:
Exception thrown at 0x00577F81 (ucrtbased.dll) in lottery.exe:
0xC0000005: Access violation writing location 0x7B7CC9FC.
If there is a handler for this exception, the program may be safely continued.
Here is my code:
void initNames(struct player *p, int size) {
int i;
for (i = 0; i < size; i++) {
printf("Enter player %d's name...\n", (i + 1));
scanf("%s", p[i].name);
}
return;
}
void initScore(struct player *p, int size) {
int i;
for (i = 0; i < size; i++) {
p[i].wins = 0;
p[i].losses = 0;
p[i].funds = 100.00;
}
return;
}
void test(struct player *p, int size) {
int i;
for (i = 0; i < size; i++) {
printf("%s, you have $%.2lf. Place your bet!\n", p[i].name, p[i].funds);
scanf("%lf", p[i].bet);
}
}
void main() {
int size;
struct player *playerPtr;
printf("How many players?");
scanf("%d", &size);
playerPtr = malloc(sizeof(struct player)*size);
initScore(&playerPtr, size);
initNames(&playerPtr, size);
test(&playerPtr, size);
free(playerPtr);
}
Thanks for any help or explanations!

Answer 1

There is a discrepancy between how you have declared the function initNames and how you are calling it in main.
It is declared as -
void initNames(struct player *p, int size);
Which means it expects a pointer to struct player as the first argument and an int as the second.
In main you are calling it as -
struct player *playerPtr;
initNames(&playerPtr, size);
Now the type of playerPtr is struct player* and thus the type of &playerPtr will be struct player**. Thus there is a type mismatch for the arguments. Your compiler should have warned you about this. Always compile with -Wall to see all the warnings and -Werror to treat warnings as errors.
Coming to the fix -
You are not going to modify playerPtr inside any of the functions. So you need not pass struct player**. So change the call to function as -
initNames(playerPtr, size);
Nothing needs to be changed inside the function because the prototype for the function hasn't been changed.
The exact same issues are with the functions initScore and test too. You can fix them in a similar way by changing the first argument to their call.
Now after fixing this too, the program won't be correct.
Look at the line -
scanf("%lf", p[i].bet);
I am assuming bet is declared with type double. You are now passing the double to scanf where a double* is expected. You need to pass the address of bet. So change the line to -
scanf("%lf", &p[i].bet);
I have fixed all the errors and the working version is at
Ideone.
I have assumed a definition for struct player.
To be more sure about the values being read you should always check the return value of scanf as -
int ret = scanf("%lf", p[i].bet);
if(ret == 0) {
// Print appropriate error message that the value entered in not a double and ask the user to retry
} else if (ret == EOF) {
// The input stream has been closed by the user without providing appropriate input, print appropriate error message and abort.
}
// If execution reaches this point, p[i].bet is safe to use.