Question

如何计算由空格分隔的文本文件中的输入整数/数字。我需要知道用户通过文件而不是从控制台输入了多少个数字。

这就是我所做的。但它会计算所有数字。

// Counting of Arrival Time //

ifstream arrival_counting;
arrival_counting.open("arrival.in");
if (arrival_counting.fail()) {
    cout << "Input file opening failed.\n" << endl;
    exit(1);
}

int count_arr = 0;
char next1;
arrival_counting.get(next1);
while(!arrival_counting.eof()) {
    if(isdigit(next1)) {
        count_arr++;
    }
    arrival_counting.get(next1);
}

// Counting of Service time //

ifstream service_counting;
service_counting.open("service.in");
if (service_counting.fail()) {
    cout << "Input file opening failed.\n" << endl;
    exit(1);
}

int count_ser = 0;
char next2;
service_counting.get(next2);
while(!service_counting.eof()) {
    if(isdigit(next2)) {
        count_ser++;
    }
    service_counting.get(next2);
}

cout << "ARRIVAL: " << count_arr << endl;
cout << "SERVICE: " << count_ser << endl;
arrival_counting.close();
service_counting.close();

arrival.in

12 31 63 95 99 154 198 221 304 346 411 455 537

service.in

40 32 55 48 18 50 47 18 28 54 40 72 12

Answer 1

ifstream arrival_counting("arrival.in");
if (arrival_counting.fail()) {
    cout << "Input file opening failed.\n" << endl;
    exit(1);
}

int count_arr = 0;
int next1;
while(arrival_counting >> next1) {
    count_arr++;
}

Answer 2

您可以在一行中计算文件中存在的数字。

你在这里。

#include <iterator>

//..

std::ifstream arrival_counting("arrival.in");

if (arrival_counting.fail()) {
    std::cout << "Input file opening failed.\n" << std::endl;
    exit(1);
}

auto n = std::distance( std::istream_iterator<int>( arrival_counting ),
                        std::istream_iterator<int>() );

在C ++中计算文本文件中的输入数字

2 个答案: