cout

I need to: Set precision so that floats are rounded to the hundredths place ( 0.111 prints as 0.11 ) Clip trailing zeros ( 1.0 prints as 1 ) Never print an exponent ( 1000.1 prints as 1000.1 ) printf( "%.2f\n", input ); // handles 1 and 3 but not 2 printf( "%.2g\n", input ); // handles 1 and 2 but not 3 cout << setprecision( 2 ) << input << endl; // handles 1 and 2 but not 3 Is there a printf or cout option that will let me handle all of these? The C11 standard says of %f and %F (7.21.6.1:8): A double argument representing a floating-point number is converted to decimal notation in the style [

I am writing a program using MPI. Each processor executes a for loop: int main(int argc, char** argv) { boost::mpi::environment env(argc, argv); for( int i=0; i<10; ++i ) { std::cout << "Index " << i << std::endl << std::flush; } } Is there a way to make the cout only happen on the last processor to hit index i? Or flag so a line is only executed on the last processor to get to it? It might look like trivial, but actually, what you ask here is extremely complex for distributed memory models such as MPI... In a shared memory environment, such as OpenMP for example, this would be trivially

Latelly I've been working with multi-thread coding, after a while writing I realized that if I used std::cout in different boost::threads, the output would came without a logical order, the program that I'm testing is something like: #include <boost/thread/thread.hpp> #include <iostream> int my01( void ) { std::cout << "my01" << std::endl; return 0; } /* my02, my03 and my04 are the same with different outputs*/ [...] int main( void ) { boost::thread t1(&my01); boost::thread t2(&my02); boost::thread t3(&my03); boost::thread t4(&my04); while(!t1.joinable() || !t2.joinable() || !t3.joinable() ||

#include <iostream> #include <cstdlib> #include <cstdio> #include <ctime> int main(int argc, char* argv[]) { std::clock_t start; double duration; std::cout << "Starting std::cout test." << std::endl; start = std::clock(); for (int i = 0; i < 1000; i++) { std::cout << "Hello, World! (" << i << ")" << std::endl; } duration = (std::clock() - start) / (double) CLOCKS_PER_SEC; std::cout << "Ending std::cout test." << std::endl; std::cout << "Time taken: " << duration << std::endl; std::system("pause"); std::cout << "Starting std::printf test." << std::endl; start = std::clock(); for (int i = 0; i <

功能要求： ​ 相关源码：码云： 传送门 ，GitHub： 传送门 相关图片： 拆分版 make编译 ​ ./hotel运行 ​ 输入2，进入开房模块 ​ 相关源码： class.cpp 1 #include <fstream> 2 #include "tools.h" 3 #include "class.h" 4 5 using namespace std; 6 7 Customer* cust[30]; 8 Room* room[30]; 9 10 11 int live; // 被订房间数 12 13 // 获取room_num 14 short Room::get_room_num(void) 15 { 16 return room_num; 17 } 18 19 // 返回房间的下标 20 int Manage::room_index(short room_num) 21 { 22 short num = room_num; 23 for(int i=0; i<30; i++) 24 { 25 if(num == room[i]->get_room_num()) 26 { 27 return i; 28 } 29 } 30 return -1; 31 } 32 33 // 返回顾客的下标 34 int Manage::cust_index(short room_num)

I'm coding a task monitoring, which updates tasks' progress using cout. I'd like to display one task progress per line, therefore I have to rollback several lines of the console. I insist on "several" because \b does the job for one line, but does not erase \n between lines. I tried std::cout.seekp(std::cout.tellp() - str.length()); but tellp() returns -1 (failure). You can do cout << '\r'; to jump to the beginning of the current line, but moving upwards is system-specific. For Unix, see man termcap and man terminfo (and search for cursor_up ). On ANSI-compatible terminals (such as most modern