error: invalid conversion from 'const char*' to 'char' [-fpermissive]

When trying to compile, I get an error saying invalid conversion from 'const char*' to 'char' [-fpermissive] using the code below. Can someone tell me what is wrong with char aAPList[2][36] = {{"",""},{"",""}};?

typedef struct {
  char acctGUID[30]     = "AAAAA-AAAAA-AAAAA-AAAAA-AAAAA";
  char SN[13]       = "1234567890AB";
  unsigned long version   = 0;
  int aSchedules[6][14]   = {{0,0,0,0,0,0,0,0,0,0,0,0,0,0},{0,0,0,0,0,0,0,0,0,0,0,0,0,0},{0,0,0,0,0,0,0,0,0,0,0,0,0,0},{0,0,0,0,0,0,0,0,0,0,0,0,0,0},{0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  char aAPList[2][36]   = {{"",""},{"",""}};
} config;  //end struct config

And a followon question - after defining that struct, I try to use a variable from it and get the following error:

error: expected primary-expression before '.' token

if (config.version > 0){

^

Why is this failing?

Thanks in advance for your expert advice!

Double quotes are for string. For char use a single quotes. ie

char aAPList[2][36]   = {{' ',' '},{' ',' '}};

Then config is not a variable it's a type. do

config myConfig;
myConfig.version = 1;

Great! Thank you.

Now it's throwing a new error:

error: empty character constant

char aAPList[2][36] = {{'',''},{'',''}};

I'm not sure that I'm thinking of this correctly. I'm trying to create structs that will be populated from an arduinoJson object. I'm initializing them with empty values at the moment. This particular variable is supposed to hold SSID/PW information for up to 2 access points on an ESP32.

error: empty character constant

Is that so hard to understand? Compare your code, with nothing between the pairs of single quotes to that of alesam who DID put something between the pairs of single quotes.

I'm sorry to offend you with my lack of knowledge! I thought this was the right place to ask questions. You're clearly the most brilliant person here - maybe you can show me what I'm missing on this next step too, then your victory will be complete!

THCGuard:365:42: error: invalid conversion from 'char' to 'const char*' [-fpermissive]

wifiMulti.addAP(config.aAPList[j][0], config.aAPList[j][1]);

^
In file included from C:\Users\somedude\Dropbox\Private\Arduino\Sketches\THCGuard\THCGuard.ino:15:0:

C:\Users\somedude\AppData\Local\Arduino15\packages\esp32\hardware\esp32\1.0.1\libraries\WiFi\src/WiFiMulti.h:43:10: note: initializing argument 1 of 'bool WiFiMulti::addAP(const char*, const char*)'

bool addAP(const char* ssid, const char *passphrase = NULL);

And if you could point me to a reference, tutorial or similar that explains clearly when and how to use strings vs char*, char**, const char* and the like so I can attempt to approach your level of magnificence, I would be indebted indeed!

As I said "config" in your case is a type of variable. Not the variable itself. You should declare a variable with type "config".

For example:

config myConfig;
myConfig.version = 1

daemach:
I'm sorry to offend you with my lack of knowledge! I thought this was the right place to ask questions. You're clearly the most brilliant person here - maybe you can show me what I'm missing on this next step too, then your victory will be complete!

THCGuard:365:42: error: invalid conversion from 'char' to 'const char*' [-fpermissive]

wifiMulti.addAP(config.aAPList[j][0], config.aAPList[j][1]);

^
In file included from C:\Users\somedude\Dropbox\Private\Arduino\Sketches\THCGuard\THCGuard.ino:15:0:

C:\Users\somedude\AppData\Local\Arduino15\packages\esp32\hardware\esp32\1.0.1\libraries\WiFi\src/WiFiMulti.h:43:10: note: initializing argument 1 of 'bool WiFiMulti::addAP(const char*, const char*)'

bool addAP(const char* ssid, const char *passphrase = NULL);

And if you could point me to a reference, tutorial or similar that explains clearly when and how to use strings vs char*, char**, const char* and the like so I can attempt to approach your level of magnificence, I would be indebted indeed!

You think you're the only and first but hardly. There are almost 1 of you every 3 days here who is confusing about free help vs monthly-payment help.