Output formatting incorrect

[khlevin]

Expected to be cleanly formatted, but is not.

The root cause of this error is that the variable `x` is initialized
to 1.0, and then iteratively multiplied by `i` in the `for` loop in
the `fact` function. However, the loop starts from `i = 0.0`, which
means that `x` will always be multiplied by 0 in the first iteration,
resulting in `x` being 0.0. The subsequent `assert` statement checks
if `x` is not equal to 0.0, which will always fail.

To fix this error, we need to initialize `x` to 1.0 instead of 0.0.
This can be done by changing the initialization of `i` in the `for`
loop to start from 1.0 instead of 0.0.

Fixed source code: ``` /* frame 0 */ /* frame 1 */ /* frame 2 */ /*
frame 3 */ /* frame 4 */ #include <assert.h> #include <iostream>

float fact(float n) {   auto x = 1.0;   for (auto i = 1.0; i < n; i++)
{     x *= i;   }   assert(x != 0.0);   ^-----------------------------
------------------------------------------------ /* frame 5 */   for
(auto i = 1.0; i < n; i++) {     x *= i;   }   assert(x != 0.0);
return x; }

int main()
{
  std::cout << fact(100) << std::endl;
  ^-----------------------------------------------------------------------------

With this fix, x will correctly accumulate the product of i values, starting from 1 instead of 0, and the assert statement will not fail.

[nicovank]

This is how we do it in CWhy: https://github.com/plasma-umass/cwhy/blob/fb99b7a07eea88a857281d0fb04997622ad1cf44/src/cwhy/cwhy.py#L13-L57

[emeryberger]

ChatDBG uses the same code, modulo single-quotes vs. double-quotes (https://github.com/plasma-umass/ChatDBG/blob/ad4624dea1deb5ae4549b8c149af2396c2d9d609/src/chatdbg/chatdbg_utils.py#L22-L65).

[emeryberger]

Pushed an updated version that correctly handles the above case.

---

The root cause of this error is that the variable x is initialized to 1.0, and then iteratively multiplied by i in the for loop in the fact function. However, the loop starts from i = 0.0, which means that x will always be multiplied by 0 in the first iteration, resulting in x being 0.0. The subsequent assert statement checks if x is not equal to 0.0, which will always fail.

To fix this error, we need to initialize x to 1.0 instead of 0.0. This can be done by changing the initialization of i in the for loop to start from 1.0 instead of 0.0.

Fixed source code:

 /* frame 0 */ /* frame 1 */ /* frame 2 */ /*
frame 3 */ /* frame 4 */ #include <assert.h> #include <iostream>

float fact(float n) {   auto x = 1.0;   for (auto i = 1.0; i < n; i++)
{     x *= i;   }   assert(x != 0.0);   ^-----------------------------
------------------------------------------------ /* frame 5 */   for
(auto i = 1.0; i < n; i++) {     x *= i;   }   assert(x != 0.0);
return x; }

int main()
{
  std::cout << fact(100) << std::endl;
  ^-----------------------------------------------------------------------------

With this fix, x will correctly accumulate the product of i values, starting from 1 instead of 0, and the assert statement will not fail.