Thread: Passing an array from within a Struct into a function...

Hi All,

I've got a struct which has several integer arrays inside of it. I'm trying to pass this struct into a function but I'm getting an error which says that the variables are not a member or something.

"error: request for '_src' in something not a structure or union"

Code:

struct temp_Packet{
    int src, dst, typ, prt;
    char data[51], buffer[51];
}temp;
//end of temp_Packet


struct SPackets{
    int _src[50], _dst[50], _typ[50], _prt[50];
    char _data[5][51];
}packets;
//end of SPackets

/********************
-----------------------
*********************/

void set_values(struct SPackets *packets, struct temp_Packet temp){
    *packets._src[nPacket] = temp.src;
    *packets._dst[nPacket] = temp.dst;
    *packets._typ[nPacket] = temp.typ;
    *packets._prt[nPacket] = temp.prt;
    strcpy(*packets._data[nPacket], temp.data);


    printf("\nSrc: %i Dst: %i Typ: %i Prt: %i Data: %s\n",
           *_src[nPacket] ,*_dst[nPacket],*_typ[nPacket] ,*_prt[nPacket],*_data[nPacket]);
}
//end of SET_VALUES

int new_packet(struct SPackets packets, int goagain, struct temp_Packet temp){


    goagain=nPacket;


    printf("\nSource Address (1-1024): ");
    scanf("%s", temp.src);


    printf("\nDestination Address (1-1024): ");
    scanf("%s", temp.dst);


    printf("\nType (0-10): ");
    scanf("%s", temp.typ);


    printf("\nData (0-50 characters): ");
    scanf("%s", temp.prt);


    set_values(&packets, temp);
    nPacket++;
//removed some coding to make it simpler to read


}
//end of NEW_PACKET
/********************
-----------------------
*********************/

int main(){

set_values(&packets, temp);

}

What I'm think the problem is that I haven't passed the struct through to the functions properly?

If there's anymore information needed to fix this I'd be more than happy to try and give it, this is doing my head in!

Thanks a lot in advance for any help that you can give!

Shini

Ah right! Well I've changed it and it finally compiles!

So something like this....

Code:

void set_values(struct SPackets *packets, struct temp_Packet temp){
    packets->_src[nPacket] = temp.src;
    packets->_dst[nPacket] = temp.dst;
    packets->_typ[nPacket] = temp.typ;
    packets->_prt[nPacket] = temp.prt;
    strcpy(packets->_data[nPacket], temp.data);


    printf("\nSrc: %i Dst: %i Typ: %i Prt: %i Data: %s\n",
           packets->_src[nPacket] , packets->_dst[nPacket], packets->_typ[nPacket] , packets->_prt[nPacket], packets->_data[nPacket]);
}
//end of SET_VALUES

Thanks for that, a quick question is the function parameters still correct though?

Ah of course, sorry about that, I'd only put in the information regarding the passing of structs into a function because I didn't realise that I had another problem.

I've put down the full code for new_packet() at the bottom it calls up set_values(). Also, I've included the coding for validate_string() and validate_datastring() which simply checks that the inputs are all integers. It's quite a stupid way of doing it but it seems to work right now. I think an alternative would be to simply check that the string that user inputs is between the ASCII values for numbers?

Also, nPacket has been declared as a global variable, though I suspect it would be much neater to declare it within the struct SPacket.

Code:

int new_packet(struct SPackets *packets, int goagain, struct temp_Packet *temp){
    char repeat='Y';
    goagain=nPacket;


    printf("\nSource Address (1-1024): ");
    scanf("%s", temp->buffer);
    temp->src = validate_string(temp->buffer, temp->src);
    while((temp->src > 1024)||(temp->src < 1)){
        printf("\nInvalid data entry, please re-enter: ");
        scanf("%s", temp->buffer);
        temp->src = validate_string(temp->buffer, temp->src);
    }


    printf("\nDestination Address (1-1024): ");
    scanf("%s", temp->buffer);
    temp->dst = validate_string(temp->buffer, temp->dst);
    while((temp->dst > 1024)||(temp->dst < 1)){
        printf("\nInvalid data entry, please re-enter: ");
        scanf("%s", temp->buffer);
        temp->dst = validate_string(temp->buffer, temp->dst);
    }


    printf("\nType (0-10): ");
    scanf("%s", temp->buffer);
    temp->typ = validate_string(temp->buffer, temp->typ);
    while(temp->typ > 10){
        printf("\nInvalid data entry, please re-enter: ");
        scanf("%s", temp->buffer);
        temp->typ = validate_string(temp->buffer, temp->typ);
    }


    printf("\nPort (1-1024): ");
    scanf("%s", temp->buffer);
    temp->prt = validate_string(temp->buffer, temp->dst);
    while((temp->prt > 1024)||(temp->prt < 1)){
        printf("\nInvalid data entry, please re-enter: ");
        scanf("%s", temp->buffer);
        temp->prt = validate_string(temp->buffer, temp->prt);
    }


    printf("\nData (0-50 characters): ");
    scanf("%s", temp->data);
    while (validate_dataString(temp->data)==false){
        printf("\nInvalid data entry, please re-enter: ");
        scanf("%s", temp->data);
    }


    set_values(&packets, &temp);
    nPacket++;


    printf("\nPacket %i created.\n\nDo you wish to create another packet?\n: ", nPacket);
    scanf("%c", &repeat);


    if((repeat=='Y')||(repeat=='y')){
        return goagain++;
    } else {
        return goagain=51;
    }
}
//end of NEW_PACKET

int validate_string(char *string, int x) /*validates that the entry consists only of ints */{
    int _strlength = strlen(string), i=0;
    for (i=0; i<_strlength; i++){
        //isdigit() not declared in C?
        if(!isdigit(string[i])){
            printf("\nInvalid entry, please re-enter: ");
            scanf("%s", string);
            validate_string(string, x);
        }
    }
    x = atoi(string);
    return x;
} //end of VALIDATE_STRING()
//end of VALIDATE STRING


bool validate_dataString(char *string){
    int _strlength = strlen(string);
    unsigned int i=0;
    for (i=0; i<_strlength; i++){
        if(!isdigit(string[i])){
            return false;
        }
    }
    return true;
}
//end of VALIDATE_DATASTRING()

The errormessage doesn't make sense as it is unless you have another variable packets in the section of main that you stripped that shadows the global packets.
Kurt

Code:

struct temp_Packet{
    int src, dst, typ, prt;
    char data[51], buffer[51];
}temp;
//end of temp_Packet

struct SPackets{
    int _src[50], _dst[50], _typ[50], _prt[50];
    char _data[51][51];
}packets;
//end of SPackets

Do you really need to setup the data structure that way? If you have to deal with single packets and a collection of packets, something like this would make it a lot easier:

Code:

struct packet_t {  /* single packet */
  int src, dst, typ, prt;
  char data[51], buffer[51];
};

struct packet_t packets[50]; /* array of packets */