An article, "Eight C++ programming mistakes the compiler won't
catch":
http://pixelstech.net/article/index.php?id=1333893320
Its Reddit thread:
http://www.reddit.com/r/cpp/comments/s0o99/eight_c_programming_mistakes_the_compiler_wont/
Some quotations from the article, valid for D too:
2) Integer division
Many new programmers attempt to do the following:
int nX = 7;
int nY = 2;
float fValue = nX / nY; // fValue = 3 (not 3.5!)
The underlying assumption here is that nX / nY will result in a
floating point division because the result is being assigned to
a floating point value. However, this is not the case.
GCC with -Wconversion finds that problem, but maybe with too much
noise:
int main() {
float fX = 7.0;
int nY = 2;
float fValue = fX / nY;
return 0;
}
...>gcc -Wconversion test.c -o test
test.c: In function 'main':
test.c:4:5: warning: conversion to 'float' from 'int' may alter
its value [-Wconversion]
4) Mixing signed and unsigned values
int nX;
unsigned int nY;
if (nX - nY < 0)
// do something
GCC with -Wconversion finds it.
There are more interesting cases with mixing short with uint, etc.
6) Side effects in compound expressions or function calls
int foo(int x)
{
return x;
}
int main()
{
int x = 5;
std::cout << foo(x) * foo(++x);
}
A good rule of thumb is to put any operator that
causes a side effect in it’s own statement.
Bye,
bearophile
