change the value of the i without changing code of the main function, assign 20 to i ?

int fun() { //write a code here /* method 1 #define fun() i=20 */ //method 2 int j; int *ptr; ptr=&j; for (;*(ptr)!=10;ptr++); *ptr=20; } int main() { int i=10; fun(); //substitute i=20 printf("%d",i); }