c union in struct
/* A union within a structure allows to use less memory to store different
* types of variables
* It allows to store only one variable described in the union instead of
* storing every variable type you need
* For example, this structure stores either an integer or a float and
* has a field which indicates what type of number is stored
*/
#include <stdio.h>
struct number
{
char *numberType;
union
{
int intValue;
float floatValue;
};
};
static void print_number(struct number n)
{
if (n.numberType == "integer")
printf("The number is an integer and its value is %dn", n.intValue);
else if (n.numberType == "float")
printf("The number is a float and its value is %fn", n.floatValue);
}
int main() {
struct number a = { 0 };
struct number b = { 0 };
a.numberType = "integer"; // this structure contains an integer
a.intValue = 10;
b.numberType = "float"; // this structure contains a float
b.floatValue = 10.56;
print_number(a);
print_number(b);
return 0;
}
/* A union is used just like a structure, the operators . and ->
* give access to the fields
*/