尝试使用数组创建随机数生成器并获取标识符 "i" 是未定义的。任何人都可以看到问题吗？

Question

尝试使用数组创建随机数生成器，但是“a[i] = rand();”我的部分代码产生了类型为“Identifier i is Undefined”的错误。谁能在这里找到我哪里出错了？谢谢

#include <iostream>
#include <string>
#include <array>

using namespace std;


int main()
{
    int a[10] = {};  
  
   
    for (int i = 0; i < size(a); i++); {

        a[i] = rand();

    }

    for (int i = 0; i < size(a); i++) {

        cout << "The random number is: " << a[i] << endl;

    }
    
}

Answer 1

$ clang++-7 -pthread -std=c++17 -o main main.cpp
main.cpp:15:11: error: use of undeclared identifier 'i'
        a[i] = rand();
          ^
main.cpp:13:38: warning: for loop has empty body
      [-Wempty-body]
    for (int i = 0; i < size(a); i++); {
                                     ^
main.cpp:13:38: note: put the semicolon on a separate line
      to silence this warning
1 warning and 1 error generated.
compiler exit status 1

clang 有助于指出您在 for 循环后有一个意外的分号。

Answer 2

您的代码中的错误是一个杂散的分号。尝试学习像 gdb 这样的调试器，将有助于解决此类问题。 rand()函数使用种子，srand()用于change/set种子。

#include <iostream>
#include <string>
#include <array>
#include <ctime>. // Added for random seed generation

using namespace std;


int main()
{
    int a[10] = {};  
  
    srand(time(0)); /* Added this to ensure seed of rand() is always different otherwise you might have ended up with same random numbers on different runs */
    
    for (int i = 0; i < size(a); i++) {   /*Issue was here, you had stray semicolon */

        a[i] = rand();

    }

    for (int i = 0; i < size(a); i++) {

        cout << "The random number is: " << a[i] << endl;

    }
    
}

尝试使用数组创建随机数生成器并获取标识符 "i" 是未定义的。任何人都可以看到问题吗？

Trying to create a random number generator using Arrays and getting Identifier "i" is Undefined. Can anyone see the problem?

c++

arrays

random

undefined

identifier