C中动态阵列的索引功能

发布于 2025-01-20 04:33:12 字数 764 浏览 2 评论 0原文

我正在编写此片段的代码，该代码无需任何错误而使用，但是当我使用valgrind运行它时，它会引发错误，有条件跳转或移动取决于非初始化的值，这是由循环试图访问数组中的第三个元素，

我的问题是我可以使用函数get_index（），因为它在使用GCC -G -WALL -PESTONTIC MAIN.C ，并输出与idx相同的索引

#include <stdio.h>
#include <stdlib.h>
#define L 3 

int *ptr;
int idx=0; // index

int get_index()
{
  int x=0;
  while(ptr[x])
    x++;
  return x;
}


void add_elem()
{
  printf("Enter your number :\n");
  scanf("%d",&ptr[idx]);
  idx++;
}


int main(void) {
  ptr = (int*)malloc(sizeof(int));

  add_elem();
  add_elem();

  printf("Current index : %d\n",get_index());
  printf("Original index : %d\n",idx);
  
  
  return 0;
}

原文

I am writing this piece of code which works without any errors but when I run it with valgrind it throws errors that Conditional jump or move depends on uninitialized value which is caused by the while loop trying to access the third element in the array

My question is can I use the function get_index() since it does not show any warnings or errors when compiling with gcc -g -Wall -pedantic main.c and outputs the same index as the idx which is declared globally

#include <stdio.h>
#include <stdlib.h>
#define L 3 

int *ptr;
int idx=0; // index

int get_index()
{
  int x=0;
  while(ptr[x])
    x++;
  return x;
}


void add_elem()
{
  printf("Enter your number :\n");
  scanf("%d",&ptr[idx]);
  idx++;
}


int main(void) {
  ptr = (int*)malloc(sizeof(int));

  add_elem();
  add_elem();

  printf("Current index : %d\n",get_index());
  printf("Original index : %d\n",idx);
  
  
  return 0;
}

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