how to advance pointer in a for loop?

[ridgerunnersjw]

Hello....
Can someone help me here as I clearly don't know what I am doing:

1. I would like to know how to create a pointer to the following structure?

2. Then how to advance the pointer to each member of the structure (same offset)?....so for instance the 2nd element Vbias[0][2], SiPM_Current[0][2], LED_Current[0][0][2], LED_Current[0][1][2]....

typedefstruct {  float Vbias[3][4]; //indexing reading 1/2/3 ; 10/50/100/200 mA
  float SiPMCurrent[3][4];  //indexing reading 1/2/3 ; 10/50/100/200 mA
  float LEDCurrent[3][2][4]; //indexing reading 1/2/3 ; LED 1/2 ; 10/50/100/200 mA
  float w_temp[3][4];  //indexing reading 1/2/3 ; 10/50/100/200 mA
  float bd_temp[3][4]; //indexing reading 1/2/3 ; 10/50/100/200 mA

} t_SenseDataRaw;

For #1 above I was trying to do the following but VS doesn't like it:

t_SenseDataRawSensorData= {0};float *pSensorData;
pSensorData = &SensorData.Vbias[0][0];

[Salem]

Can you post your code without the horrible colour scheme from your IDE.

Copy as text
Paste as text

[ridgerunnersjw]

t_SenseDataRaw SensorData = {0};float *pSensorData;
pSensorData = &SensorData.Vbias[0][0];




typedef struct {
  float Vbias[3][4]; //indexing reading 1/2/3 ; 10/50/100/200 mA
  float SiPMCurrent[3][4];  //indexing reading 1/2/3 ; 10/50/100/200 mA
  float LEDCurrent[3][2][4]; //indexing reading 1/2/3 ; LED 1/2 ; 10/50/100/200 mA
  float w_temp[3][4];  //indexing reading 1/2/3 ; 10/50/100/200 mA
  float bd_temp[3][4]; //indexing reading 1/2/3 ; 10/50/100/200 mA
} t_SenseDataRaw;

[hamster_nz]

2) You can't.

You most probably want to do something like this:

#include <stdio.h>


typedef struct {
  float Vbias;
  float SiPMCurrent;
  float LEDCurrent;
  float w_temp;
  float bd_temp;
} t_SenseDataRaw;


t_SenseDataRaw rawData[3][4]; //indexing reading 1/2/3 ; 10/50/100/200 mA


int main(void) {
   t_SenseDataRaw *ptr = rawData[2];
   for(int i = 0; i < 4; i++, ptr++) {
      printf("%f\n",ptr->Vbias);
      printf("%f\n",ptr[i].Vbias);  // Same thing
   }
   return 0;
}

[christop]

Could you instead use an index variable (let's call it i as an example) that you use in each member, e.g., SensorData.Vbias[0][i], SensorData.SiPMCurrent[0][i], etc.? Without more information on exactly why you need to have a pointer to the same element in each member, this smells like an XY problem.

Edit: I like hamster_nz's answer. Consider reorganizing your structure to do what you want to do.