Thread: strcat

I am trying to get a better understanding of c strings I always seem to see myselft missing a big gap everytime I program something I am trying to replace strcat(for a better understanding) The code compiles and runs but I think it hits and infinite loop

Code:

#include <stdio.h>

int main(void){
        char fname[256];
        char lname[256];
        int x=0,y=0;
        printf("Enter your first name: ");
        fflush(stdout);
        fgets(fname,sizeof fname,stdin);
        printf("Enter your last name: ");
        fflush(stdout);
        fgets(lname,sizeof lname,stdin);
        while(fname[x]!='\n'){
                x++;
        }
        fname[x]=' ';
        x++;
        printf("%s\n",fname);
        while(lname[y]!='\n'){
                fname[x]=lname[y];
        }
        printf("%s\n",fname);
        return 0;
}