Login name

gistfile1.c

//---------------------------------------------------------------------------
//---------------------------------------------------------------------------

#include <conio.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>

char * stringToUpper(char * str) {
    for(int i = 0; i < (int)strlen(str); i++)
        str[i] = toupper(str[i]);
    return str;
}

void loginName() {
    char name[15], vorname[15], login[9];
    FILE * fptrIn;
    FILE * fptrOut;

    fptrIn = fopen("name.txt" , "r");
    fptrOut = fopen("login.txt" , "w");
    
    if(fptrIn == NULL) perror("Error opening file");
    else {
        if(fptrOut == NULL) perror("Error opening file");
        else {
            while(!feof(fptrIn)) {
                fscanf(fptrIn, "%s", name);
                fscanf(fptrIn, "%s", vorname);
                if(strlen(name) >= 6) {
                    strncpy(login, stringToUpper(name), 6);
                } else {
                    strcpy(login, stringToUpper(name));
                    for(int i=1; i <= (int)(6 - strlen(name)); i++) {
                        strcat(login, "x");
                    }
                }
                login[6] = vorname[0];
                login[7] = vorname[1];
                login[8] = '\0';
                fprintf(fptrOut, "%s\n", login);
                getch();
            }
        }
    }
    fclose(fptrIn);
    fclose(fptrOut);
}

int main() {
    loginName();
    getch();
}