いくつかのパラメータ伝達問題(c++primer plusを読む)

1:配列でパラメータを渡す

#include   <iostream>

#include <cmath>



struct polar
{

double distance;:

double angle;

};
struct rect
{
double x;
double y;
}

void rect_to_polar(const *pxy,polar *pda);
void show_polar(const polar *pda);

int main()
{

rect rplace;
polar pplace;

while (cin >> rplace.x >> rplace.y)
{
rect_to_polar (&rplace,&pplace);
show_polar(&pplace)
}
return 0;
}

void show_polar(const polar* pda)
{
    using namespace std;
    cout <<pda->distance;
    cout << pda->angle;
}

void rect_to_polar (const rect *pxy,polar *pda)

{
using namespace std;
pda->distance =
sqrt(pxy ->x+pda->y*pda->y);
}
      ，                    ,      。

3：    ：

#include <iostream>

double betsy(int);

double pam(int);

void estimate (int lines,double (*pf)(int));

int main()

{

    using namespace std;

    int code;

    cin >> code;

    estimate (code,betsy);

    estimate(code,pam);

    return 0;

}

double betsy(int lns)

{

    return 0.05*lns;

}

double pam (int lns)

{

    return 0.03*lns + 0.0004*lns*lns;

}

void estimate (int lines,double(*pf)(int))

{

    using namespace std;

    cout << (*pf)(lines) ;

}

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ol.mainarea li{ display:list-item !important; font-size:12px !important; margin:0 !important; line-height:18px !important; padding:0 0 0 0px !important; background-color:#f7f7ff !important; color:#4f81bd}
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ol.mainarea li pre.alt{ background-color:#f7f7ff !important}

function CopyCode(key){var codeElement=null;var trElements=document.all.tags("ol");var i;for(i=0;i<trElements.length;++i){if(key.parentElement.parentElement.parentElement==trElements[i].parentElement.parentElement){codeElement=trElements[i];break}}if(codeElement!=null){var content=codeElement.innerText;if(window.clipboardData==null){window.alert(「ブラウザではスクリプトコピーはサポートされていません.手動でコピーしてみてください.」)Else{window.clipboardData.setData("Text",content);window.alert("ソースコードはクリップボードにコピーされました")}}}}function LineNumberVisible(key){var codeElement=null;var trElements=document.all.tags("ol");var i;for(i=0;i<trElements.length;++i){if(key.parentElement.parentElement.parentElement==trElements[i].parentElement.parentElement){codeElement=trElements[i];break}}if(codeElement!=null){if(codeElement.className=="mainarea number_hide"){codeElement.className="mainarea number_show";key.innerText="行番号を隠す"}else{codeElement.className="mainarea number_hide";key.innerText="行番号を表示する"}}function ChangeIcon(key,isHover){if(isHover)key.style.cor='red';else key.style.cor='blue'}function CopyCode_CheckKey(key){if(window.event.keyCode==13)CopyCode(key)}function AboutMe(){window.alert("このコードボックスはCodePaste for Windows Live Writerによって生成されます.r
r
Author:範伝根r
Email:[email protected]\r
Website: http://chuangen.name\r
Blog: http://blog.csdn.net/chuangen");}
2回目にestimate()関数を呼び出すと関数pam()のアドレスが渡されます.つまり*pfポインタです.pf=pam