Cpp size_t 0 is smaller than minus one

Table of Contents

Be careful with your loops

size_t zero=0;
long minus_one=-1;
EXCPECT_FALSE( zero < minus_one ); // should be false, but in fact is true

Why that matters?
I got this bug:

long limit = -1; // default value was designed to skip the loop
...
if( .. ) { limit = optionalCalculatedValue; }
...
for( size_t i=0; i<limit; i++) {
    // infinite loop on default limit value
}

Also, there was similar but less obvious situation is same project:

for( size_t i=0; i<parameter-1; i++) {
    // infinite loop if parameter is 0
}

You can fix it like this:

for( size_t i=0; i+1<parameter; i++) {
    // now it's ok
}