如何在运行时增加数组大小以避免最后的垃圾值

Question

Here i am working with a code which will count the number of "1" present in an array at a time.say, my array is

int arr[12] = {0,1,1,0,0,1,1,1,1,0,0,1};

Number of "1" present at a time are (2,4,1)

I want to store the result in an array calle store .As the sequence can vary,At the very beginning i don't know what size of array i have to declare to store them.Worst case will be there might be a array like the following:

int arr[12]={0,1,0,1,0,1,0,1,0,1,0,1};

so i dynamically allocated an array half the size of actual array to store the worst case.But If not the worst case i get garbage value at the end of store array.I would like to know how i can dynamically increase array size at runtime so that i don't need to deal with any garbage value

#include<stdio.h>
#include<stdlib.h>

int main(){

   int arr[12] = {0,1,1,0,0,1,1,1,1,0,0,1};
   int size = sizeof(arr)/sizeof(arr[0]);

   int *store =(int *)malloc((size/2)*sizeof(int));

   int i=0,j=0,count=0;
   while(arr[i]<size){
        while(arr[i]==0 && arr[i]<size){
            i++;
        }
        if(i==size){
           break;
        }
        while(arr[i]==1){
            i++;
            count++;
        }
        store[j]=count;
        j++;
        count=0;
   }
   for(i=0;i<size/2;i++){

       printf("%d ",store[i]);
   }

}

Answer 1

Use realloc

//size2 has the size of the new array to be stored
store = realloc(store, size2 * sizeof int);

if (store == NULL)
{
   // Reallocation failed -- Take appropriate action
   printf ("Reallocation failed");
   exit(1);
}

Answer 2

您可以使用calloc

store = calloc(store,sizeof(int));