STL Vectors call by reference using vectors of structure

[Digital Don]

I have a problem sending the Vectors as Referencial parameters..i.e . I am having a struct vector

 
struct board
{
     int r;
     int c;
};
 
void rd(vector <struct board> cp)
{
cout<<"\nr="<<cp[0].r;
cp[0].r=8;
}
//---------------------
/*This Read function should catch the vector reference and 
any modification done to this cp should affect the cpy in main()*/
//---------------------
void read(vector <struct board> cp)
{
for(int i=0;i<4;i++)
for(int j=0;j<4;j++)
{
struct board x;
x.r=i;
x.c=j;
cp->push_back(x);
} 
rd(*cp);
cout<<"\nr="<<cp[0].r;
//---------------------------------------
/*How do I access the r and c in the cp? I have tried a lot of thinsg but
was unsuccessful in accessing the r and c in cp[0]? */
//---------------------------------------
}
void main()
{
 
vector <struct board> cpy;
 
read(&cpy);
 
for(int i=0;i<4;i++)
//for(int j=0;j<4;j++)
cout<<"\nCpy took "<<cpy[i].r<<" , "<<cpy[i].c<<endl;
//-------------------
Any effects in the functions to cpy by call by 
reference should affect this cpy too...
}
 

I have 2 problems....

1 is call by reference for vector array variables...

2 is accessing the r and c in the cpy struct variable through the pointer?


Please help....

I was actually trying to use the single dimentional array for declaring this i.e.
struct board x[50];

but this said that I was supposed to initialize all the variables as this was not easy I thought of shifting to vectors and now I have this problem...

Thank You in advance...

Regards,
Digital Don...

[horace1]

you should be able to pass vectors by reference using & so

void read(vector <struct board> &cp)
{
for(int i=0;i<4;i++)
for(int j=0;j<4;j++)
{
struct board x;
x.r=i;
x.c=j;
cp.push_back(x);
} 
rd(cp);
cout<<"\nr="<<cp[0].r;
}
 

and call it

vector <struct board> cpy;
read(cpy);
 

[horace1]

I was actually trying to use the single dimentional array for declaring this i.e.
struct board x[50];

Thank You in advance...

Regards,
Digital Don...

not sure what your problem is with an array, e.g.

void rd(struct board cp[50])
{
cout<<"\nr="<<cp[0].r;
cp[0].r=8;
}
//---------------------
/*This Read function should catch the vector reference and 
any modification done to this cp should affect the cpy in main()*/
//---------------------
void read(struct board cp[50])
{
int index=0;
for(int i=0;i<4;i++)
for(int j=0;j<4;j++)
{
struct board x;
x.r=i;
x.c=j;
cp[index++]=x;
} 
rd(cp);
cout<<"\nr="<<cp[0].r;
//---------------------------------------
/*How do I access the r and c in the cp? I have tried a lot of thinsg but
was unsuccessful in accessing the r and c in cp[0]? */
//---------------------------------------
}
int main()
{
 
struct board cpy[50];
 
read(cpy);
 
for(int i=0;i<4;i++)
//for(int j=0;j<4;j++)
cout<<"\nCpy took "<<cpy[i].r<<" , "<<cpy[i].c<<endl;
//-------------------
//Any effects in the functions to cpy by call by 
//reference should affect this cpy too...
system("pause");
}
 

arrays are passed by reference so you don't need the &

[Digital Don]

The problem with arrays was that it was asking me to "initialliz e the array" which I declared in Main()...and declaring a 'n' sized array is not a good idea...

Thanks for the help regarding the VECTORS...

not sure what your problem is with an array, e.g.

void rd(struct board cp[50])
{
cout<<"\nr="<<cp[0].r;
cp[0].r=8;
}
//---------------------
/*This Read function should catch the vector reference and 
any modification done to this cp should affect the cpy in main()*/
//---------------------
void read(struct board cp[50])
{
int index=0;
for(int i=0;i<4;i++)
for(int j=0;j<4;j++)
{
struct board x;
x.r=i;
x.c=j;
cp[index++]=x;
} 
rd(cp);
cout<<"\nr="<<cp[0].r;
//---------------------------------------
/*How do I access the r and c in the cp? I have tried a lot of thinsg but
was unsuccessful in accessing the r and c in cp[0]? */
//---------------------------------------
}
int main()
{
 
struct board cpy[50];
 
read(cpy);
 
for(int i=0;i<4;i++)
//for(int j=0;j<4;j++)
cout<<"\nCpy took "<<cpy[i].r<<" , "<<cpy[i].c<<endl;
//-------------------
//Any effects in the functions to cpy by call by 
//reference should affect this cpy too...
system("pause");
}
 

arrays are passed by reference so you don't need the &