pointer

[myidealbook]

WHAT IS DIFFERENT BETWEEN THIS.
char *ptr="hello";
char ptr[]="hello";

[myidealbook]

//what Is Different Between Overloading And Overlapping .

[myidealbook]

#include<iostream.h>
#include<conio.h>
int sum(double,double);
int sum(int,int);
void main()
{
clrsscr();
cout<<sum(12.456,34.677);
cout<<sum(13,56);
getch();
}
/*
THIS IS RIGHT OR NOT
*/

[myidealbook]

//what is different between .
struct student s;//student is user define data type
struct student *s;

[myidealbook]

//what is different between .
struct student s;//student is user define data type
struct student *s;//

struct student *s;
s=new student;
s=new student[5];
s=new student[];

[horace1]

WHAT IS DIFFERENT BETWEEN THIS.
char *ptr="hello";
char ptr[]="hello";

some examples

    char *s = "hello";            // "hello" is a constant, s is pointer at it   
    char a[30] = "hello";         // define an array, initialise it with    "hello"
    *(s+2) = 'X';                 // ERROR! change second element of char*pointed to by s 
                                  //   would give run time segmentation error
    a[2] = 'X';                  // OK change second element of array a
    s=a;                         // point s at array a
    *(s+2) = 'Z';                // OK change second element of string pointed to by , i.e. a[2]
 

[horace1]

#include<iostream.h>
#include<conio.h>
int sum(double,double);
int sum(int,int);
void main()
{
clrsscr();
cout<<sum(12.456,34.677);
cout<<sum(13,56);
getch();
}
/*
THIS IS RIGHT OR NOT
*/

you have overloaded function sum(), one takes two double parameters and the other takes two int paramters. So when you call sum() in main() it calls the corect version. There were a few minor bugs in your code but this version works

#include<iostream.h>
#include<conio.h>
double sum(double,double);
int sum(int,int);
int main()
{
//clrsscr();    // ** not available on all compilers
cout<<sum(12.456,34.677) << endl;
cout<<sum(13,56) << endl;
getch();
}
double sum(double x,double y) { return x + y; }
int sum(int x,int y) { return x + y; }
 

when run it gives
47.133
69


note if you call sum() so

cout<<sum(13,56.0) << endl;
 

the compiler will not know which version to call and gives error message

10 C:\tue\x1.cpp call of overloaded `sum(int, double)' is ambiguous 
 note C:\tue\x1.cpp:3 candidates are: double sum(double, double) 
 note C:\tue\x1.cpp:3                 int sum(int, int) 
 

[pragatiswain]

Simple words :

char *ptr="hello"; //ptr contains the location address of hello.
char ptr[]="hello"; // ptr contains hello.

Please correct me, if I am wrong

[horace1]

Simple words :

char *ptr="hello"; //ptr contains the location address of hello.
char ptr[]="hello"; // ptr contains hello.

Please correct me, if I am wrong

in
char *ptr="hello";
"hello" is a constant and ptr contains the address of it
you cannot change the contents of "hello"

in
char ptr[]="hello";
"hello" is an array and ptr contains the address of it
You can change the contents of hello