我有兴趣阅读.txt文件,并将数据保存在C中的矩阵中.
dist.txt is the following:
Distance Amsterdam Antwerp Athens Barcelona Berlin
Amsterdam - 160 3082 1639 649
Antwerp 160 - 2766 1465 723
Athens 3082 2766 - 3312 2552
Barcelona 1639 1465 3312 - 1899
Berlin 649 723 2552 1899 -
事实上它有更多的城市,但没关系.
我想阅读这份文件并记录距离.我试过以下代码:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>
#define rows 6
#define cols 6
int main()
{
FILE *nansa;
char *buffer;
int ret,row=0,i,j;
char delims[]=" \t";
char *result=NULL;
double **mat=malloc( rows*sizeof(double*) );
for(i=0; i<rows; i++)
{
mat[i]=malloc( …我有以下字符串"2012-09-04T00:11:20.000Z"我需要将此字符串转换为灰壳的时间戳.
怎么做？
我有这个linux命令:
candump -l -e -x -s 0 -n 10 any,0~0,#FFFFFFFF 2>/dev/null> /tmp/can.log&
当我直接在shell中运行它时,它可以正常工作.
我想用这个方法在我的脚本中添加它:
#!/bin/sh
# I tried this 2 syntax
# MYVAR="candump -l -e -x -s 0 -n 10 any,0~0,#FFFFFFFF 2> /dev/null > /tmp/can.log &"
MYVAR='candump -l -e -x -s 0 -n 10 any,0~0,#FFFFFFFF 2> /dev/null > /tmp/can.log &'
$MYVAR
当我执行我的脚本时,我收到此错误:
SIOCGIFINDEX:没有这样的设备
我测试了这些脚本并且它有效:
#!/bin/sh
MYVAR='ls -l'
$MYVAR
结果:
total 8
drwxr-xr-x 2 root root 0 Nov 5 2015 bin
drwxr-xr-x 2 root root 0 Oct 22 2015 boot
drwxr-xr-x …#define MY_MACRO 3 --> in A.h
#define MY_MACRO 45 --> B.h
//In C.cpp
#include "A.h"
#include "B.h"
..
..
..
int my_value = MY_MACRO;
my_value是3还是45？
我试图从https://github.com/augcampos/asterisk-cpp/wiki/Examples编译此示例,但我收到此错误:
root@debian:~# g++ TesteCpp.cpp -o tt -lasteriskcpp
TesteCpp.cpp: In function ‘int main()’:
TesteCpp.cpp:13:39: error: invalid conversion from ‘void (*)(asteriskcpp::ManagerEvent*)’ to ‘asteriskcpp::onManagerEventCallback_t {aka void (*)(const asteriskcpp::ManagerEvent&)}’ [-fpermissive]
In file included from TesteCpp.cpp:4:0:
/usr/local/include/asteriskcpp/manager/ManagerConnection.h:49:14: error: initializing argument 1 of ‘void asteriskcpp::ManagerConnection::addEventCallback(asteriskcpp::onManagerEventCallback_t)’ [-fpermissive]
怎么解决？
TesteCpp.cpp:
//TesteCpp.cpp
#include <iostream>
#include "asteriskcpp/utils/LogHandler.h"
#include "asteriskcpp/manager/ManagerConnection.h"
using namespace asteriskcpp;
void eventCallback(ManagerEvent* me) {
std::cout << std::endl << "TEST:EVENT" << me->toLog() << std::endl;
}
int main() {
ManagerConnection mc;
mc.addEventCallback(&eventCallback); // add event listener
if (mc.connect("192.168.1.6")) …我有功能
$x = 012;
echo $x / 3;
为什么结果是3.33333？
但如果我使用:
$x = '012';
那是对的.问题是如何解释这个？