如何在C ++中使用空格输入长字符串？

Question

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int T;
    cin >> T;
    char input[1000];
    for(int i=0;i<T;i++)
    {
        cin.getline(input,sizeof(input));
        cout << input << "\n";
    }
    return 0;
}

I am currently having problem getting string input using getline but it seems to work only for short lines. Here is my input and output:

Input:

3 Can I have a large container of coffee right now Can I have a large container of tea right now Now I wish I could recollect pi Eureka cried the great inventor Christmas Pudding Christmas Pie Is the problems very center

Output:

Can I have a large container of coffee right now Can I have a large container of tea right now

It doesn't store last line why?

Answer 1

You can do it with this way, using string instead of char [] :

int main() {
    int T;
    cin >> T;
    string input;
    for(int i=0;i<T;i++)
    {
        std::getline(std::cin,input);
        cout << input << endl;
    }
    return 0;
}

Check the code with the following test :

Input :

3 Can I have a large container of coffee right now Can I have a large container of tea right now Now I wish I could recollect pi Eureka cried the great inventor Christmas Pudding Christmas Pie Is the problems very center

Output:

3 Can I have a large container of coffee right now Can I have a large container of tea right now Now I wish I could recollect pi Eureka cried the great inventor Christmas Pudding Christmas Pie Is the problems very center

Answer 2

Your problem is the first input operator:

cin >> T;

This reads a number and stores it as an integer in T, but leaves the newline in the stream. Now the loop will read three lines, but the first will be an empty line.

You can fix this in several ways, the simplest is to just discard the newline after fetching the number:

cin >> T;
cin.getline(input, sizeof input);

A better way will be to check for end of file instead of fetching the number of lines in advance. And use std::string instead of char arrays as others have suggested.

Answer 3

Try something like this

while(cin.getline(input,sizeof(input))){
}

Answer 4

Try:

int main() {
    int T;
    cin >> T;
    std::string temp;
    std::string input;
    for(int i=0;i<T;i++)
    {
        while(std::getline(std::cin,temp)) {
        input += temp;
    }
    std::cout << input << endl;
    return 0;
}