小编JBR*_*RPG的帖子

我对C++内存管理很陌生,因为与C不同,释放所有内存还有更多障碍.

我试图成功删除任何类型的矢量指针(即矢量*数据)

/** 
 * We test the program in accessing vectors
 * with dynamic storage
**/
#include <iostream>
#include <vector> // you must include this to use vectors

using namespace std;

int main (void){
    // Now let's test the program with new and delete
    // for no memory leaks with vectors (type safe)
    // however, just calling delete is not enough to free all memory
    // at runtime
    vector <int> * test_vect = new vector <int> (10,5);

    // Print out …

当我在线阅读一些在线网站提供的代码时,我宁愿遇到一个我从未预料到的奇怪故障:变量突然改变其值而没有任何手动分配.

这是下面的代码:

int rc = fwrite(conn->db, sizeof(struct Database), 1, conn->file);
printf("rc is equal to %d\n", rc); // should print out 1
if (rc != 1) die("Failed to write Database.");

rc = fflush(conn->file);
printf("rc is equal to %d\n", rc); // should print out 0
if (rc == -1); die("Cannot flush database"); // error handling
// error comes up because rc suddenly changes to -1

我不明白它是如何发生的,但是想知道为什么变量突然在C中突然发生变化.

代码来源:http: //c.learncodethehardway.org/book/learn-c-the-hard-waych18.html (Database_write下的堆栈和内存)

顺便说一下,我在Mac osx 10.6雪豹的终端上使用vim.