pointer-address | 易学教程

Pointer address does not change in a link list

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问题 My problem is q->next always prints the same address, but I assigned q = &x; . Why it is not printing different addresses? #include <stdio.h> class Node { public: int val; Node *next; Node(int v,Node *p) { val=v, next=p; } }; int main() { Node head(0, NULL); Node *q = &head; int i = 5; while (i>0) { Node x(i * 10, q); q = &x; printf("# %d %p\n", q->val, q->next); i--; } } 回答1: This has to do with the way x is allocated: It is a local variable inside the main function. That means it is

Why pointer is giving two different addresses?

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问题 I have this program. And I have some doubts. You can run it in your compiler. I am using gcc compiler in linux #include<stdio.h> int main() { int j=4,*add; int i=2; int a[i][j]; for (i=0;i<=1;i++) { for(j=0;j<=3;j++) { scanf("%d",&a[i][j],"%d",&a[i][j]); } } for(i=0;i<=1;i++) { for (j=0;j<=3;j++) { add=&(a[i][j]); printf("\nSize of %d is %d and address is: %u that should be equal to: %d",a[i][j],sizeof(a[i][j]),&(a[i][j]),add);//Address are not equal while add is having the value of &(a[i][j]

Goto a specific Address in C

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问题 How can I JMP to a specific address in C? I want to use goto 0x10080000 This is not working, is there other way I can change the address of Program Counter?? 回答1: You can cast the address to a function pointer and then jump into: ((void (*)(void))0x10008000)(); To make it a bit more clear: typedef void (*func_t)(void); ... ((func_t)0x10008000)(); But this is a function, the compiler will emit a branch instruction that expect to return (then is up to you to make your function return or not).

Assigning a pointer in a struct to a variable

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问题 This program is supposed to create a dynamic memory vector. I'm pretty sure I'm using malloc correctly. My real problem is some syntax with pointers, particularly a pointer inside a struct. I'm trying to access the address of an int pointer inside a struct so I can assign it to another pointer My given struct is: typedef struct{ int *items; int capacity; int size; }VectorT; and the function I'm trying to get to work is: int getVector(VectorT *v, int index){ int *p; p = v->items;//(2) p -= v-

Is the order of memory addresses of successively declared variables always descending?

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问题 why does the hexadecimal value of pointer address returned is always in decreasing order? for example here int a was declared before int d , so it's address always comes out to be greater than d , and same for &b , &e and &c , &f , I want to know that is this a fixed behavior or is this compiler dependent? I am using gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-1 ) #include<stdio.h> int main(void){ int a=1; int d=1; char b='a' ; char e='a'; float c=1.0; float f=1.0; printf("a=%p\nd=%p\nb=%p\ne=%p

Is the order of memory addresses of successively declared variables always descending?

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why does the hexadecimal value of pointer address returned is always in decreasing order? for example here int a was declared before int d , so it's address always comes out to be greater than d , and same for &b , &e and &c , &f , I want to know that is this a fixed behavior or is this compiler dependent? I am using gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-1 ) #include<stdio.h> int main(void){ int a=1; int d=1; char b='a' ; char e='a'; float c=1.0; float f=1.0; printf("a=%p\nd=%p\nb=%p\ne=%p\nc=%p\nf=%p\n",&a,&d,&b,&e,&c,&f); if (&a>&d) printf("&a>&d\n"); else {printf("&a<&d"); } if (&a>&d &&

Weird Pointer Address for Individual Struct Data Member

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问题 I observe some weird behavior today , the code is as follow : The Code : #include <iostream> struct text { char c; }; int main(void) { text experim = {'b'}; char * Cptr = &(experim.c); std::cout << "The Value \t: " << *Cptr << std::endl ; std::cout << "The Address \t: " << Cptr << std::endl ; //Print weird stuff std::cout << "\n\n"; *Cptr = 'z'; //Attempt to change the value std::cout << "The New Value \t: " << *Cptr <<std::endl ; std::cout << "The Address \t: " << Cptr << std::endl ; //Weird

Weird Pointer Address for Individual Struct Data Member

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I observe some weird behavior today , the code is as follow : The Code : #include <iostream> struct text { char c; }; int main(void) { text experim = {'b'}; char * Cptr = &(experim.c); std::cout << "The Value \t: " << *Cptr << std::endl ; std::cout << "The Address \t: " << Cptr << std::endl ; //Print weird stuff std::cout << "\n\n"; *Cptr = 'z'; //Attempt to change the value std::cout << "The New Value \t: " << *Cptr <<std::endl ; std::cout << "The Address \t: " << Cptr << std::endl ; //Weird address again return 0; } The Question : 1.) The only question I have is why cout theAddress for the