我发现了很多关于从 Delphi 到 C++ 的主题，但仍然感到困惑。
std::string s1(" look here ");
将它传递给delphi代码的正确方法是什么？
这些都不起作用，产生错误的字符
char * s = (char *)s1.c_str();
Call_Delphi_func(s);
.......
Memo1.Lines.Add(UTF8String(PChar(pointer(s))));
我试图获取一个数字的因子并将它们的值输入到一个数组中，小数字工作正常，但是当我尝试使用大数字时，代码崩溃了。
#include <iostream>
#include <math.h>
using namespace std;
main(){
int num,c=1,a[c],b;
cin>>num;
for(int i=1; i <= num; i++) {
if (num % i == 0)
a[c++]=i;
}
cout<<a[6];
}
据我所知,while循环可以这样做:
while (true) {
// run this code
if (condition satisfies)
break; // return;
}
所以我接受了它并且我在下面输入了以下主要功能,我的问题是当我在满足条件(5或更多)后放置一个printf语句时,它会停止并且不显示任何内容,如果我什么也没放,它工作的break语句循环通过5个不同的客户!我错过了关于while循环的任何内容,或者这是它的工作方式吗？
int main ()
{
displayMenu();
while (true)
{
int gasType,gallonsAmount,carWashOption,customerAmount ;
float gasPrices[SIZE]={2.99,3.099,3.199,3.299}, washPrices[SIZE]=
{3.50,3.00,3.00,2.50}, perGallonRate,perWashRate,total;
float totalSum,totalGallonSum;
gasType = getGasType();
gallonsAmount = getGallons();
carWashOption = getCarWash();
perGallonRate = getGallonRate(gasPrices, gasType);
if (carWashOption == 'Y')
{
perWashRate = getWashRate( washPrices, gasType );
total = calcAmount(gallonsAmount, perGallonRate, perWashRate,&totalSum, &totalGallonSum);
}
else
{
perWashRate = 0;
total = calcAmount(gallonsAmount, perGallonRate, perWashRate,&totalSum, &totalGallonSum);
}
customerAmount++;// once we …我希望程序继续要求值进行计算,直到标志为真,然后程序必须停止,但它只执行一次.我不知道我是否以正确的方式使用char,或者是否有更好的方法来执行带有标志的这些类型的while循环.任何帮助都会很棒.[在此处输入图片说明] [1]
int main()
{
displayMenu();
bool flag = false;
while(!flag)
{
int choice = 0; int val1 = 0; int val2 = 0; int ans = 0;
cout << "Enter your choice (1-5): ";
cin >> choice;
cout << "\nEnter integer 1: ";
cin >> val1;
cout << "\nEnter integer 2: ";
cin >> val2;
if(choice < 0 || choice > 5)
{
cout << "\nEnter a choice between 1-5: ";
cin >> choice;
}
if (choice == 1) …我正在从事一个编码项目，遇到了一些麻烦。当我尝试制作时，出现以下错误：
src/mean.cc:26:12: error: passing ‘const csce240::Mean’ as ‘this’ argument discards qualifiers [-fpermissive]
pop_back();
^
In file included from /usr/include/c++/7/list:63:0,
from inc/mean.h:9,
from src/mean.cc:2:
/usr/include/c++/7/bits/stl_list.h:1152:7: note: in call to ‘void std::__cxx11::list<_Tp, _Alloc>::pop_back() [with _Tp = double; _Alloc = std::allocator<double>]’
pop_back() _GLIBCXX_NOEXCEPT
^~~~~~~~
src/mean.cc:33:29: error: passing ‘const csce240::Mean’ as ‘this’ argument discards qualifiers [-fpermissive]
push_front(tempList.back());
^
In file included from /usr/include/c++/7/list:63:0,
from inc/mean.h:9,
from src/mean.cc:2:
/usr/include/c++/7/bits/stl_list.h:1067:7: note: in call to ‘void std::__cxx11::list<_Tp, _Alloc>::push_front(const value_type&) [with _Tp = double; _Alloc = std::allocator<double>; std::__cxx11::list<_Tp, …为什么当我输入与数组中的数字匹配的费用数字时，我的程序无法运行。请参考函数
#include <iostream>
#include <cmath>
using namespace std;
string returnWord(int arr[], int SZ)
{
int nums = 0;
string answer;
cout << "Please enter a charge number: ";
cin >> nums;
for (int i = 0; i < SZ; i++) {
if (nums == arr[i]) {
answer = "This is Valid";
}
else {
answer = "This is Invalid"; // When I enter the valid number this is what prints out
}
}
return (answer);
}
int main()
{
const …在函数标题/ prototype之后const之前和const之间有什么区别？另外在下面的例子中做什么？
例如.
const E& top() const throw(StackEmpty);
如果我们用4个元素初始化数组,例如:
int array[4];
我们可以分配这样的值,因为它还带有4个值:
for(int i=5;i<9;i++){
cin>>array[i];
}