C++ for Scientists - Technische Universität Dresden

236 CHAPTER 10. PROGRAMMING TOOLS
The -DNDEBUG option sets the C-preprocessor variable NDEBUG which tells the assert command
that debug tests should not be done. This allows us to save time at execution.
10.2 Debugging
10.2.1 Debugging with text tools
“Et la tu t’dis que c’est fini
car pire que ça ce serait la mort.
Qu’en tu crois enfin que tu t’en sors
quand y en a plus et ben y en a encore!”
— Stromae.
There are several debugging tools. In general, graphical ones are more user friendly, but they
are not always available. In this section, we describe the gdb debugger, which is very useful to
trace the cause of a run time error if the code was compiled with the option -g.
The following contains a printout of a gdb session of the program hello.cpp:
#include
#include
int main() {
glas::dense vector< int > x( 2 ) ;
x(0) = 1 ; x(1) = 2 ;
for (int i=0; i