What is the problem with this code?

Question

#include<iostream>
#include<sstream>
#include<string>
using namespace std;

int main()
{
string str = "";
int n;
cin >> n;
cin.ignore();

for(int i = 0; i < n; i++) {‌‌‌‌‌‌‌
string name, first, last;
getline(cin, name);
stringstream ss(name);
ss >> first >> last;
str += first[0];
str += last[0];
if(i < n-1) {
str += " ";
}
}
cout << str << endl;
return 0;
}

Answer 1

Hey,

The code works as expected. But the line ` for(int i = 0; i < n; i++) {‌‌‌‌‌‌‌` seems to contain some invalid characters (shows up for me as <200c>).

That's likely why u are getting the error.

Answer 2

The primary problem with the provided code is the cin.ignore() call immediately after cin >> n;. When cin >> n; reads the integer, it leaves the newline character in the input buffer. The subsequent cin.ignore() consumes one character, which is indeed that newline. However, if the user inputs n and then presses Enter, there's only one newline. If there's any other whitespace after n before the newline, cin.ignore() might not consume the intended character. A more robust approach for discarding the rest of the line after reading an integer is cin.ignore(numeric_limits<streamsize>::max(), '\n');. Without this, the first getline(cin, name); in the loop might read an empty string if there were extra characters or another newline left in the buffer from the integer input. Also, first[0] and last[0] could cause a crash if first or last are empty strings (e.g., if the user enters only a single name or an empty line).