multiple errors on one line - C

Hey guys... i'm new to the programming scene, i'm totally lost as to how to fix this problem.

Function:

Code:

---


typedef struct{
                        char id;
                        double x;
                        double y;
                        double power;
                        double radius;
                        }towers_t;

void
stage_2(towers_t stage_1){
int i=0;
while(i<MAXTOWERS){
        if(i==EOF){
        }
        else{
                towers[i].radius = 10.0*pow((towers[i].power/PMIN),.25)-10.0);
                i++;
        }

        printf("Tower %c at (%4lf,%4lf) transmitting %.2lf W has a signal radius %4lf\n", towers.id, towers.x, towers.y, towers.power, towers.radius);
}
}

---

The error is on the line with the calculation.
The problems are stated as :

• syntax error
• subscripted value is neither array nor pointer
• syntax error before ')' token

> towers.radius[i] =
None of what you've posted is an array (that's the "subscripted value is neither array nor pointer")

towers isn't an array.
Each member of the struct isn't an array either.

then how would i pass values into a single structure member already existing in an array of structures?
To clarify:
In my first function i have already put values into a struct. In my 2nd function i want to add to that same struct. That struct is part of an array with other structs of the same type, and i want to be able to enter the values for towers.radius with this single calculation.

Hope that clears up what im trying to say.

Show us how you're calling stage2

Are you passing just one element of the array from the caller?

i'm not calling stage2. im passing stage1 into stage2.

stage 1 has the user input data for id, x, y and power and it puts that into the 1st structure of an array. If the user puts in a new line of data it puts that into a 2nd structure of the array, and so on.

in stage 2 i'm passing in stage1. i just want to add an extra member of information via the calculation then print out a table.

*edit* sorry i put the wrong input for stage_2 (fixed it)

Not enough information.

Is stage1 an array of towers, or just one?

stage1 is an array of many towers.

i have found another of ur posts taht i maybe could use to show wat i mean.
you posted this in another recent post:

Code:

---

struct pet menagerie[3];  // all my pets

menagerie[0].species = "Labrador";
menagerie[0].name = "Scooby";
menagerie[0].numLegs = 4;

menagerie[1].species = "Parrot";
menagerie[1].name = "Polly";
menagerie[1].numLegs = 2;

menagerie[2].species = "Goldfish";
menagerie[2].name = "Jaws";
menagerie[2].numLegs = 0;

---

basically i have all my species' and name's filled in via stage1 but not the numLegs'. I now want to compute the data for numLegs' in stage2.
...perhaps the way i'm approaching it is not proper? @~@

Ok i did something... i don't really remember what i did...i was jsut playing around with it but i've managed to get it down to one error.

Code:

---

void
stage_2(towers_t stage_1){
int i=0;
while(i<MAXTOWERS){
        if(i==EOF){
        }
        else{
                towers[i].radius = (10.0*pow((towers[i].power/PMIN),.25)-10.0);
                i++;
        }

        printf("Tower %c at (%4lf,%4lf) transmitting %.2lf W has a signal radius %4lf\n",
                        towers.id, towers.x, towers.y, towers.power, towers.radius);

---

error: `towers' undeclared (first use in this function)

Quote:

---

Originally Posted by djdato

error: `towers' undeclared (first use in this function)

---

Well, like it says, "towers" is undeclared.

Code:

---

void
stage_2(towers_t stage_1){
int i=0;
while(i<MAXTOWERS){
        if(i==EOF){
        }
        else{
                towers[i].radius = (10.0*pow((towers[i].power/PMIN),.25)-10.0);
                i++;
        }

---

The declared variables in stage_2() are red. I don't see any named "towers".

im not sure if what i'm doing is possible...
but i'm trying to pass in stage_1 which returns an array called 'towers'.
Is there a way to modify an array which is outside the function? Or can I pass that array into the function?

pass the arrays address and size into the function

ex.

Code:

---

#include <stdlib.h>
#include <stdio.h>

void func(int arr_size, int* arr)
{
//this function initializes the arr array that it receives from main
int i;
for(i=0;i<arr_size;++i)
        arr[i] = i+1;
}

int main()
{
int k;
int *myarray = malloc(100*sizeof(int));
func(100,myarray); //myarray is a pointer
for(k=0;k<100;++k) printf("%d ", myarray[k]);

// or with a static array
int myarray2[100];
func(100,&myarray2[0]);
for(k=0;k<100;++k) printf("%d ", myarray2[k]);
}

---

since now 'func' has the actual location of the array, it can modify it and any changes made reflect back in main.

thanks guys. fixed it. did what rodrigo told me to do.