need to produce a function that detects the zeros in a array - c++

Question

I have this code but is not working , it keep giving me the following errors :
[Error] cannot convert 'float' to 'float*' for argument '1' to 'void zeroCrossing(float*, float*, int)'
[Error] cannot convert 'float*' to 'float' for argument '1' to 'bool getSign(float)'
[Error] cannot convert 'float*' to 'float' for argument '1' to 'bool getSign(float)'
[Error] invalid conversion from 'int' to 'float*' [-fpermissive]
#include <iostream>
#include <cstring>
using namespace std;
void zeroCrossing(float *data, float *zerCross, int nx);
bool getSign(float data);
float array[9] = {1,2,3,0,-1,-2,-3,0,1};
float *p = array;
float f1[9];
float *p2 = f1;
int bx= 2 ;
int main() {
zeroCrossing(*p,*p2,bx);
return 0 ;
}
/* zero crossing function */
/* data = input array */
/* zerCross = output zero crossing array */
void zeroCrossing(float *data[], float *zerCross[], int nx)
{
int i;
bool sign1, sign2;
memset(zerCross, 0, nx*sizeof(float));//copies the 0 to the first characters of the string
//pointed to, by argument
for(i=0; i<nx-1; i++) /* loop over data */
{
sign1 = getSign(data[i]);
sign2 = getSign(data[i+1]);
if(sign1!=sign2) /* set zero crossing location */
zerCross[i+1] = 1;
}
}
/* get sign of number */
bool getSign(float data)
{
if(data>0) /* positif data */
return (1);
else /* negatif data */
return (0);
}

Answer 1

When you do coding, you should compile the code after some lines of codes, unless you are pro.
There are two things I could say about your codes
Function declaration: void zeroCrossing(float *data, float *zerCross, int nx); and void zeroCrossing(float *data[], float *zerCross[], int nx) are not the same.
Variable name: Should avoid names like array because they are used in the standard lib.
This is my fix to make your code compilable
#include <iostream>
#include <cstring>
using namespace std;
void zeroCrossing(float *data, float *zerCross, int nx);
bool getSign(float data);
float array_[9] = {1,2,3,0,-1,-2,-3,0,1};
float* p = array_;
float f1[9];
float *p2 = f1;
int bx= 2 ;
/* get sign of number */
bool getSign(float data)
{
if(data>0) /* positif data */
return (1);
else /* negatif data */
return (0);
}
/* zero crossing function */
/* data = input array */
/* zerCross = output zero crossing array */
void zeroCrossing(float *data, float *zerCross, int nx)
{
int i;
bool sign1, sign2;
memset(zerCross, 0, nx*sizeof(float));//copies the 0 to the first characters of the string
//pointed to, by argument
for(i=0; i<nx-1; i++) /* loop over data */
{
sign1 = getSign(data[i]);
sign2 = getSign(data[i+1]);
if(sign1!=sign2) /* set zero crossing location */
zerCross[i+1] = 1;
}
}
int main() {
zeroCrossing(p,p2,bx);
return 0 ;
}

Answer 2

1 - you should minimize the number of global variables, in your case it is 0.
2 - *p points to a value stored in an address p, so in main function when you are calling zeroCrossing you need to pass an address, not value.
To be honest, I don't understand what you are trying to do but at least this code don't throw errors:
#include <iostream>
#include <cstring>
using namespace std;
void zeroCrossing(float *data, float *zerCross, int nx);
bool getSign(float data);
int main()
{
float array[9] = {1,2,3,0,-1,-2,-3,0,1};
float *p = array;
float f1[9];
float *p2 = f1;
int bx = 2 ;
zeroCrossing(p, p2, bx);
return 0 ;
}
/* zero crossing function */
/* data = input array */
/* zerCross = output zero crossing array */
void zeroCrossing(float *data, float *zerCross, int nx)
{
int i;
bool sign1, sign2;
memset(zerCross, 0, nx*sizeof(float));//copies the 0 to the first characters of the string
//pointed to, by argument
for(i=0; i<nx-1; i++) { /* loop over data */
sign1 = getSign(data[i]);
sign2 = getSign(data[i+1]);
if(sign1!=sign2) /* set zero crossing location */
zerCross[i+1] = 1;
}
}
/* get sign of number */
bool getSign(float data)
{
if(data>0) /* positif data */
return (1);
else /* negatif data */
return (0);
}