What is the difference between array[i]++
and array[i++]
, where the array is an int array[10]
?
问题:
回答1:
int a[] = {1, 2, 3, 4, 5};
int i = 1; // Second index number of the array a[]
a[i]++;
printf("%d %d\n", i, a[i]);
a[i++];
printf("%d %d\n", i, a[i]);
Output
1 3
2 3
a[i]++
increments the element at index i
, it doesn't increment i
. And a[i++]
increments i
, not the element at index i
.
回答2:
array[i]++
increments the value ofarray[i]
. The expression evaluates toarray[i]
before it has been incremented.array[i++]
increments the value ofi
. The expression evaluates toarray[i]
, beforei
has been incremented.
An illustration.
Suppose that array
contains three integers, 0, 1, 2, and that i
is equal to 1.
array[i]++
changesarray[1]
to 2, evaluates to 1 and leavesi
equal to 1.array[i++]
does not modifyarray
, evaluates to 1 and changesi
to 2.
A suffix operators, which you are using here, evaluates to the value of the expression before it is incremented.
回答3:
array[i]++
means ( *(array+i) )++
. --> Increments the Value.
array[i++]
means *( array + (i++) )
. --> Increments the Index.
回答4:
Here the Array[i]++
increments the value of the element array[i]
,
but array[i++]
increments the i
value which effects or changes the indication of the array element (i.e. it indicates the next element of an array after array[i]
).
回答5:
#include<iostream>
using namespace std;
int main()
{
int arr[]={1,2,37,40,5,7};
int i = 3;
arr[i]++;
cout<<i<<" "<<arr[i]<<endl;
arr[i++];
cout<<i<<" "<<arr[i]<<endl;
return 0;
}
output:
3 41
4 5
In this example i = 3 so,arr[3]= 40 and then it increases the value 40 to 41.So arr[i]++ increments the value of this particular index and a[i++] first increment the index and then gives the values of this index.
回答6:
Here array[i++]
increments the index number.
On the contrary, array[i]++
increments the data value of i
index.
Code Snippet:
#include <iostream>
using namespace std;
int main()
{
int array[] = {5, 2, 9, 7, 15};
int i = 0;
array[i]++;
printf("%d %d\n", i, array[i]);
array[i]++;
printf("%d %d\n", i, array[i]);
array[i++];
printf("%d %d\n", i, array[i]);
array[i++];
printf("%d %d\n", i, array[i]);
return 0;
}
回答7:
Let's say we have this example, array[i++] = x[m++]
. This means that first set array[i] = x[m]
then increase the indexes like i + 1
, m + 1
.