Generating Uniformly Distributed Pseudo-random Numbers in C++

Generating Uniformly Distributed Pseudo-random Numbers in C++

In cplusplus.com reference it's stated that, using modulo operator when
trying to generate random numbers will make lower numbers more likely:
random_var = rand() % 100 + 1; //this will generate numbers between 1-100
Why are lower numbers more likely? And if they're, why aren't we using
this code below :
random_var = rand()/(RAND_MAX/100) + 1; //also will generate those, more
uniform I guess