malloc study

gistfile1.txt

#include <stdio.h>
#include <stdlib.h>

void ChangeValue(int *pointer_array, int mos, int new_value){
        *(pointer_array+mos) = new_value;
}

int main()
{   
    int n = 3;
    int i, *ptr, sum = 0;
    
    ptr = (int*) malloc(n * sizeof(int));

    for(i = 0; i < n; ++i)
    {   
        *(ptr+i) = i;
        printf("*(ptr+i) is: %d | *(ptr) is: %d | ptr is: %p\n",*(ptr+i),*ptr,ptr);
        printf("ptr+i is: %p\n================================================\n",(ptr + i));
        ChangeValue(ptr,i,i*2);
    }
    for(i = 0; i < n; ++i)
    {
        printf("*(ptr+i) is: %d | *(ptr) is: %d | ptr is: %p\n",*(ptr+i),*ptr,ptr);
    }   
    
    free(ptr);
    return 0;
}
/*
int main()
{
        int a[5]={1,2,3,4,5};
        int *p;
        p=(int *)(&a+1);
        printf("%d,%d ",*(a+1),*(p-1));
        return 0;
}
*/