Array increment types in C - array[i]++ vs array[i++]

Question

array[i]++和array[i++]之间有什么区别，其中数组是一个 int array[10] ？

Answer 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 .

Answer 2

• array[i]++ increments the value of array[i] . The expression evaluates to array[i] before it has been incremented.
• array[i++] increments the value of i . The expression evaluates to array[i] , before i has been incremented.

An illustration.

Suppose that array contains three integers, 0, 1, 2, and that i is equal to 1.

• array[i]++ changes array[1] to 2, evaluates to 1 and leaves i equal to 1.
• array[i++] does not modify array , evaluates to 1 and changes i to 2.

A suffix operators, which you are using here, evaluates to the value of the expression before it is incremented.

Answer 3

array[i]++ means ( *(array+i) )++ . --> Increments the Value.

array[i++] means *( array + (i++) ) . --> Increments the Index.

Answer 4

这里Array[i]++增加元素array[i] ，但array[i++]增加i值，这会影响或改变数组元素的指示（即它指示 array 之后的array[i]的下一个元素array[i] ）。

Answer 5

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 .

Answer 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;
}

Answer 7

#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.