I am quite new to C programming. I encountered this error while compiling my program. I have tried to look around the internet for a solution but to no avail. The error is on the line num = rand()%20;
char* getParameter(char *name)
{
char *num;
char *buffer;
if(strcmp(name,"Trainingsprogramm")){
srand (time(NULL));
num = rand()%20;;
sprintf(buffer,"%d",num);
}else if(strcmp(name,"Personnenummer")){
srand (time(NULL));
num = rand()%20;
sprintf(buffer,"%d",num);
}else if(strcmp(name,"Tretzustand")){
srand (time(NULL));
srand (time(NULL));
num = rand()%20;
sprintf(buffer,"%d",num);
}else if(strcmp(name,"Tretleistung")){
srand (time(NULL));
num = rand()%20;
sprintf(buffer,"%d",num);
}else if(strcmp(name,"Drehzahl")){srand (time(NULL));
num = rand()%20;
sprintf(buffer,"%d",num);
}else if(strcmp(name,"Geschwindigkeit")){srand (time(NULL));
num = rand()%20;
sprintf(buffer,"%d",num);
}else if(strcmp(name,"GefahreneDistanz")){srand (time(NULL));
num = rand()%20;
sprintf(buffer,"%d",num);
}else if(strcmp(name,"RealeKJoule")){srand (time(NULL));
num = rand()%20;
sprintf(buffer,"%d",num);
}else if(strcmp(name,"AktuellerPuls")){srand (time(NULL));
num = rand()%20;
sprintf(buffer,"%d",num);
}else if(strcmp(name,"MomentanerGang")){srand (time(NULL));
num = rand()%20;
sprintf(buffer,"%d",num);
}else if(strcmp(name,"RelaxBetrieb")){srand (time(NULL));
num = rand()%20;
sprintf(buffer,"%d",num);
}else if(strcmp(name,"VerbrauchteKJoule")){srand (time(NULL));
num = rand()%20;
sprintf(buffer,"%d",num);
}
return buffer;
}