Mapping string to int CPP - Output hangs during execution - c++

Question

I am currently doing a practice problem in hacker rank. The link is : https://www.hackerrank.com/challenges/linkedin-practice-dictionaries-and-maps
#include<cstdio>
#include<map>
#include<vector>
#include<conio.h>
#include<iostream>
#include<string>
using namespace std;
map<std::string, int> dict;
map<std::string, int>::iterator k;
int i, j, temp, n;
long long num;
//char check[100][100];
std::string str, sea;
int main()
{
scanf("%d", &n);
j = n;
while(j--)
{
scanf("%s %d", &str, &num);
dict.insert(make_pair(str, num));
}
printf("finished\n");
printf("%s %d\n", "sam", dict["sam"]);
while(scanf("%s", str))
{
if(str.empty())
break;
//printf("k is %s\n",str);
k = dict.find(str);
if(k != dict.end())
{
printf("%s %d\n", str, dict[str]);
}
else
{
printf("Not found\n");
}
}
getch();
}
The program runs fine until the printf statement "finished". Then in the next output for the dict statement occurs as
finished
sam 0
And in while statement, when it searches for string in map, the application hangs, and closes automatically. While inserting values I tried to use:
dict[str] = num;
dict.insert(pair(str, num));
dict.insert(make_pair(str, num));
Please mention if there is any corrections I need to do in the program. Any help is appreciated. Thanks!

Answer 1

This statement,
scanf("%s %d", &str, &num);
… is not a valid way to input a std::string. It has Undefined Behavior. All bets are off.
You can input to a char buffer, and conveniently std::string provides such a buffer. E.g.
str.resize( max_item_length );
scanf("%s %d", &str[0], &num);
str.resize( strlen( &str[0] ) );
Of course you can just use C++ iostreams instead, throughout the code, e.g.
cin >> str >> num;