evaluation of expression which is used with sizeof

c, expression, sizeof

Solution

Your array is not a variable-length array. A variable length array is an array whose size is not a constant expression. For example, `data` is a variable-length array in the following:

int i = 10;
char data[i];

To see an example of a code that has `sizeof` evaluate its operand, try something like this:

#include <stdio.h>

int main(void)
{
    int i = 41;
    printf("i: %d\n", i);
    printf("array size: %zu\n", sizeof (char[i++]));
    printf("i now: %d\n", i);
    return 0;
}

It prints:

i: 41
array size: 41
i now: 42

Problem

Is there any expression that would be evaluated as operand of a sizeof. I have come to know in case of variable length operand with sizeof, the expression would be evaluated. But I cant make an example, I wrote the code below, ``` int a[]={1,2,3}; printf("%d",sizeof(a[1]++)); printf("%d\n",a[1]); ``` but here I observed from output expression `a[1]++` is not evaluating. how to make an example??

Original source

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