No their is no online converter. In C you havent any classes and so you must decompose your MersenneTwister class.
A possible solution is, that all data members from that class becoming an struct, and your functions get a pointer to that struct as input.
struct MersenneTwister {
int data;
} _MersenneTwister;
void init( _MersenneTwister* twister ); void print( _MersenneTwister* twister ); void random( _MersenneTwister* twister );
The out you must replace with
print. Look at the sample code to understand the usage.