Программа пропускает cin

#pragma once
#define _CRT_SECURE_NO_WARNINGS
#include "targetver.h"
#include <stdio.h>
#include <iostream>
#include <tchar.h>

#include "stdafx.h"
 
using namespace std;
 
struct Man {
    char surName[80];
    char name[80];
    int num;
};
 
const int nPeople = 20;
 
Man people[nPeople];
 
 
int compareBySurName(const void* a, const void* b) {
    const Man* A = (const Man*)a;
    const Man* B = (const Man*)b;
 
    return strcmp(A->surName, B->surName);
}
 
int compareByName(const void* a, const void* b) {
    const Man* A = (const Man*)a;
    const Man* B = (const Man*)b;
 
    return strcmp(A->name, B->name);
}
 
int compareByNum(const void* a, const void* b) {
    const Man* A = (const Man*)a;
    const Man* B = (const Man*)b;
 
    return A->num - B->num;
}
 
int baseCreating(){
    const int bufSize = 200;
 
    char buf[bufSize];
 
    cout << "0. Generate\n1. Load\n";
 
    cin.getline(buf, bufSize);
 
    if (strncmp(buf, "0", 1) == 0) {
        for (int i = 0; i < nPeople; i++) {
            people[i].num = rand() % 100;
 
 
            const int maxlen = 10;
            const int minlen = 3;
 
            int len = rand() % (maxlen - minlen) + minlen;
 
            const char vowels[] = "eyuioa";
            const char consonants[] = "qwrtpsdfghjklzxcvbnm";
 
            for (int j = 0; j < len; j++) {
                people[i].name[j] = (j & 1) ? vowels[rand() % 6] : consonants[rand() % 20];
            }
 
            buf[len] = 0;
 
            cout << people[i].num << "\t" << people[i].name << endl;
 
        }
    }
 
    if (strncmp(buf, "1", 1) == 0) {
        FILE*  fs = fopen("c:/ITstep/people.dat", "rb");
        if (fs == nullptr) {
            perror("error reading file people.dat");
            return 0;
        }
 
        int res = fread(people, sizeof(Man), nPeople, fs);
        if (res != nPeople) {
            cout << "file not complete\n";
        }
 
        fclose(fs);
    }
 
    qsort(people, nPeople, sizeof(Man), compareByNum);
 
 
    for (int i = 0; i < nPeople; i++) {
        cout << people[i].num << "\t" << people[i].name << endl;
    }
 
    // SAVE
 
 
    FILE*  fs = fopen("c:/ITstep/people.dat", "wb");
    if (fs == nullptr) {
        perror("error writing file people.dat");
        return 0;
    }
 
    fwrite(people, sizeof(Man), nPeople, fs);
 
    fclose(fs);
 
    cout << "Data successfully saved\n";
 
    return 0;
}
 
int mainMenu(){
    while (1 + 1 != NULL){
        int mainSwitch = -1;
        cout << "______________________________________MENU______________________________________\n"
            "0) Exit\n"
            "1) Create base\n"
            "2) Sort by any paraneter\n"
            "3) Create key (index)\n"
            "4) Show any sorted parameter\n"
            "\n"
            "Enter number of what operation you want to do: \n";
        cin >> mainSwitch;
        switch (mainSwitch){
        case 0:{
            return 0;
        } break;
        case 1:{
            cout << "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Base creating~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~" << endl;
            baseCreating();
        } break;
        case 2:{
 
        }break;
        case 3:{
 
        }break;
        case 4:{
 
        }break;
 
        }
    } return 0;
}
int main()
{
    mainMenu();
    return 0;
}
 
//1. Create people.dat with numbers, names, and surnames
//2. Sort and create 3 indexes
//3. Make a console menu

(cin >> mainSwitch).get();