cout

How does cout's << operator work with regard to operator precedence? [duplicate]

由 余生长醉 提交于 2019-12-23 16:06:55
问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Unexpected order of evaluation (compiler bug?) I couldn't predict the output for this program : #include<iostream> using namespace std; int *p(int *a) { (*a)++; return a; } int main() { int i=0; cout<<i++<<" "<<(*p(&i))++<<" "<<i++<<" "<<i<<endl; return 0; } When compiled in vs2008, it outputs 3 2 0 4 . Can anybody explain why it's not 0 2 3 4 ? Note: It works great if there is no function call to p . Thanks in

How does cout's << operator work with regard to operator precedence? [duplicate]

由 你。 提交于 2019-12-23 16:04:00
问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Unexpected order of evaluation (compiler bug?) I couldn't predict the output for this program : #include<iostream> using namespace std; int *p(int *a) { (*a)++; return a; } int main() { int i=0; cout<<i++<<" "<<(*p(&i))++<<" "<<i++<<" "<<i<<endl; return 0; } When compiled in vs2008, it outputs 3 2 0 4 . Can anybody explain why it's not 0 2 3 4 ? Note: It works great if there is no function call to p . Thanks in

C++ STL Heap算法

由 别说谁变了你拦得住时间么 提交于 2019-12-23 13:47:06
#include <iostream> #include <algorithm> #include <vector> using namespace std; int main() { 　　vector<int> vec1; 　　vector<int>::iterator vec_iter1; 　　for (int k=0;k<10;k++) 　　{ 　　　　vec1.push_back(rand()); 　　} 　　for (vec_iter1 = vec1.begin();vec_iter1 != vec1.end();++vec_iter1) 　　{ 　　　　cout << *vec_iter1 << " "; 　　} 　　cout << endl; 　　cout << "-------------------------------------------------------" << endl; 　　make_heap(vec1.begin(), vec1.end()); 　　for (vec_iter1 = vec1.begin(); vec_iter1 != vec1.end(); ++vec_iter1) 　　{ 　　　　cout << *vec_iter1 << " "; 　　} 　　cout << endl; 　　cout << "--------------

C++ SegFault when dereferencing a pointer for cout

由 徘徊边缘 提交于 2019-12-23 10:09:43
问题 I'm new to C++ and just trying to get a hang of it. It generally seems not too bad, but I stumbled upon this weird/pathological segfaulting behavior: int main () { int* b; *b = 27; int c = *b; cout << "c points to " << c << endl; //OK printf( "b points to %d\n", *b); //OK // cout << "b points to " << (*b) << endl; - Not OK: segfaults! return 0; } This program, as given, produces what you'd expect: c points to 27 b points to 27 On the other hand, if you uncomment the second-to-last line, you

How to output unicode in C++ without _setmode

由 匆匆过客 提交于 2019-12-23 09:48:15
问题 I'm trying to insert a unicode value, in this case, \u250F, or ┏, to the console output. I have searched around, and people recommending a variety of things. Before we discuss on what I tried, I am using Windows and Visual Studio 2013. The main error When I try multiple 'fixes', if not specified, I always get the same error: Debug Assertion Failed! Program: ...nts\visual studio 2013\Projects\roguelike\Debug\roguelike.exe File: f:\dd\vctools\crt\crtw32\stdio\fputc.c Line: 48 Expression: ((

Eclipse Debug run and console run of the same program give different outputs

由 旧城冷巷雨未停 提交于 2019-12-23 05:44:12
问题 So this is in reference to my older question which I fixed. Now the issue is that when I run my program (code as follows)... #include <stdio.h> #include <memory.h> #include <string> #include <iostream> using namespace std; #include "timesync.h" FILE * CTimeSync::pipe = NULL; int CTimeSync::TimeSyncCheck() { char szPipeBuffer [200]; string strPipeOutput; memset( szPipeBuffer, 0, sizeof(szPipeBuffer) ); CTimeSync::pipe = popen( "ntpq -np", "r" ); if ( CTimeSync::pipe ) { while ( !feof(

Getting last char sent to std::cout

由 限于喜欢 提交于 2019-12-23 03:15:21
问题 I need at the end of main() execution to check if last char sent to stdout (through std::cout ) was '\n' (or platform specific end-of-line). How to test for this? It is safe to assume that C style io (like printf) was not used. Program is REPL for C++. It evaluates C++ expressions (or statements) and prints results on stdout. It is desirable that output would be always terminated with single new-line. 回答1: It is similar answer to this given by @Kevin. However I believe it is better for your

Getting last char sent to std::cout

由 ╄→гoц情女王★ 提交于 2019-12-23 03:15:09
问题 I need at the end of main() execution to check if last char sent to stdout (through std::cout ) was '\n' (or platform specific end-of-line). How to test for this? It is safe to assume that C style io (like printf) was not used. Program is REPL for C++. It evaluates C++ expressions (or statements) and prints results on stdout. It is desirable that output would be always terminated with single new-line. 回答1: It is similar answer to this given by @Kevin. However I believe it is better for your

tsp蛮力法(dfs)

由 假装没事ソ 提交于 2019-12-23 00:54:47
#include <iostream> #include <stdlib.h> #include <queue> #include <stack> #include <fstream> #include <iomanip> // 本文用于输出对齐 using namespace std; const int max_vexNum = 20; bool is_visited[max_vexNum]; int path_num = 0; int bestLength = 10000000; int path_index = 0; int path_DFS[max_vexNum][max_vexNum]; double lenth_DFS[max_vexNum]; typedef struct { int vex_num, arc_num; // 顶点数 边数 double arcs[max_vexNum][max_vexNum]; // 邻接矩阵 }Graph; int _findCityIndex(Graph G, int city_start) { for (int i = 0; i < G.vex_num; i++) { if (i== city_start) { return i; } } cout << "【error】当前城市未找到！" << endl; return -1

C++ reset locale to “C” globally?

由 我是研究僧i 提交于 2019-12-22 04:10:51
问题 In a project I am currently working on I link to a proprietary dynamic library. As soon as I run the library's initialize function, the behavior of logging and printing of numbers changes. Commas have been inserted at every third decimal. Ie. cout << 123456789 << endl used to print out 123456789 and now it prints 123,456,789 . This is horribly annoying, because this behavior is not what I want. This issue is not only apparent in the binary I am compiling, but also shows up in all the couts
订阅 cout