gist1.c

#include<stdio.h>

void wrong_change(int);
void correct_change(int*);


int main() {
   int number = 5;
   printf("the number now is : %d\n",number);

   wrong_change(number);
   printf("the number now is : %d\n",number);


   correct_change(&number);
   printf("the number now is : %d\n",number);

   return 0;
}

void wrong_change(int number) {
   int num;
   num = number;
   num++;
}

void correct_change(int *addr) {
   int *num;
   num = addr;
   *num = 6;
}