Question

此代码编译并运行虽然给出了我无法修复的Microsoft编译器错误

警告C4700：未初始化的本地变量＆＃39;＆＃39;用过的。

这是代码的最后一行，我想

#include <iostream>
using namespace std;

const int DIM0 = 2, DIM1 = 3, DIM2 = 4, DIM3 = 5;

void TestDeclar();

int main(){
    TestDeclar();
    cout << "Done!\n";
    return 0;
}

void TestDeclar(){        
    //24 - array of 5 floats
    float xa[DIM3], xb[DIM3], xc[DIM3], xd[DIM3], xe[DIM3], xf[DIM3];
    float xg[DIM3], xh[DIM3], xi[DIM3], xj[DIM3], xk[DIM3], xl[DIM3];   
    float xm[DIM3], xn[DIM3], xo[DIM3], xp[DIM3], xq[DIM3], xr[DIM3];
    float xs[DIM3], xt[DIM3], xu[DIM3], xv[DIM3], xw[DIM3], xx[DIM3];

    //6  - array of 4 pointers to floats
    float *ya[DIM2] = {xa, xb, xc, xd}, *yb[DIM2] = {xe, xf, xg, xh};   
    float *yc[DIM2] = {xi, xj, xk, xl}, *yd[DIM2] = {xm, xn, xo, xp};
    float *ye[DIM2] = {xq, xr, xs, xt}, *yf[DIM2] = {xu, xv, xw, xx};

    //2 - array of 3 pointers to pointers of floats
    float **za[DIM1] = {ya, yb, yc};    
    float **zb[DIM1] = {yd, ye, yf};

    //array of 2 pointers to pointers to pointers of floats
    float ***ptr[DIM0] = {za, zb};   
    cout << &***ptr[DIM0] << '\n';  
}

Answer 1

您正在访问ptr4D的末尾。 DIM0是2，比最后一个1的索引大一个！

将最后几行更改为：

//array of 2 pointers to pointers to pointers of floats
float ***ptr4D[DIM0] = {za, zb};   
cout << &***ptr4D[0] << '\n';

Answer 2

不确定我是否可以帮助你，但我试图找出试图在我的linux机器上运行它的错误。我已经在ubuntu机器上编译它来进行比较并且它没问题，甚至告诉编译器打开所有选项警告（传递-Wall选项）。跑步时，我得到了这个：

# Compiled it with -Wall to enable all warning flags and -g3 to produce extra debug information
~$ g++ -Wall stackoverflow.cpp -g3
./a.out 
Segmentation fault (core dumped)

然后我尝试用GDB（GNU调试器）调试它并得到了这个：

(gdb) r
Starting program: /home/ubuntu/a.out 

Program received signal SIGSEGV, Segmentation fault.
0x0000000000400986 in TestDeclar () at stackoverflow.cpp:34
34          cout << &***ptr4D[DIM0] << '\n';  
(gdb) s

所以看来问题出在cout线上。再次检查代码， DIM0 的值为 2 ，因此您尝试访问ptr4D之外的内存地址。如上所述user1721424，只需将 DIM0 替换为 0 即可完成！

#After fixing it:
~$ ./a.out 
0x7fff74cd3830
Done!

希望它有所帮助！

未初始化的局部变量

2 个答案: