Structure Assignments in C,C++

The information contained in one structure may be assigned to another structure of the
same type using a single assignment statement. That is, you do not need to assign the
value of each member separately. The following program illustrates structure
assignments:
#include <stdio.h>
int main(void)

 {
struct {
int a;
int b;
} x, y;
x.a = 10;
y = x; /* assign one structure to another */
printf("%d", y.a);
return 0;
}
After the assignment, y.a will contain the value 10.

Pointer Assignments in C,C++

As with any variable, you may use a pointer on the right-hand side of an assignment
statement to assign its value to another pointer. For example,
#include <stdio.h>
int main(void)
{
int x;
int *p1, *p2;
p1 = &x;
p2 = p1;
printf(" %p", p2); /* print the address of x, not x's value! */
return 0;
}
Both p1 and p2 now point to x. The address of x is displayed by using the %p printf()
format specifier, which causes printf() to display an address in the format used by the
host computer.

Shorthand Assignments

There is a variation on the assignment statement, sometimes referred to as a shorthand

assignment, that simplifies the coding of a certain type of assignment operation. For

example,

x = x+10;

can be written as

x += 10;

The operator += tells the compiler to assign to x the value of x plus 10.

This shorthand works for all the binary operators (those that require two

operands). In general, statements like:

var = var operator expression

can be rewritten as

var operator = expression

For another example,

x = x-100;

is the same as

x -= 100;

Shorthand notation is widely used in professionally written C/C++ programs; you

should become familiar with it.