Thread: string copy question

hi there , i am writing a prg which is the same as the library strcpy function ..

could u guys check out my prg because it is copying b to a but at the end it is giving me some other char ..

//************************************************** *
#include<iomanip.h>
#include<string>
//************************************************** *
//prototypes
void myStrcpy(char a[], char b[]);
//************************************************** *
const int MAX = 10;

//************************************************** *
void main()
{ char a[MAX],
b[MAX];

myStrcpy(a, b);

}
//************************************************** *
void myStrcpy(char a[], char b[])
{
int num,
ct;

cout << "Enter the word" ;
for(ct = 0 ; ct <= 5 ; ++ct){
cin >>ws;
cin>> b[ct]; }

do{
for(ct = 0 ; b[ct]!='\0' ; ++ct){
a[ct]= b[ct] ;}
}while(b[ct]!= '\0');
cout << "b is copied to a and now a is" << a << endl;
}

From a quick glance at your code, it seems you are not copying the NULL termination character. You need to copy this, and them terminate.

Alternatively, you could use memcpy to copy the string contents, and set the byte after the last character copied to be NULL.

i am nwe to this so please could u show me hoe to do that.

Code:

void myStrcpy(char a[], char b[])
{
    int     num, ct;
    cout << "Enter the word" ;
    for(ct = 0 ; ct <= 5 ; ++ct){
        cin >>ws;
        cin>> b[ct];
    }
    // Why not:
    cin.getline(b,MAX-1);
    
    do{ //This loop is useless
        for(ct = 0 ; b[ct]!='\0' ; ++ct){
            a[ct]= b[ct] ;
        }
    }while(b[ct]!= '\0'); // You should set '\0' to the end of a.
    cout << "b is copied to a and now a is" << a  << endl;
}

OK WHEN I USE cin.getline it si giving me the following error

Error E2285 C:\srt_cpy.cpp 29: Could not find a match for 'istream::getline(char,int)' in function myStrcpy(char *,char *)

and i removed the do while loop and just used while

while(b[ct]!= '\0')---> this is giving the copied value

BUT
when i used this one

while(a[ct]!= '\0') ---> this is giving some garbage values

i dont know what i am doing wrong..

cin.getline(b,MAX-1);

could u explain to me why did u use MAX-1 [ can i say
cin.getline(b,sizeof(b)) instead of cin.getline(b,MAX-1); ]

a[ct]='\0';
if i assign a[ct] the null char what about the contents it copied from b ..