关于#c++#的问题：我运行时响应特慢

各位，帮忙看看这demo里有什么问题，我运行时响应特慢

#include 
#define pi 3.1415926
#define p2 6.2831852
using namespace std;

int main(void){
    char choose;
    cout << "请输入要输入的数据类型"<< endl;
    cout << "直径输d,半径输r,周长输c(严格区分大小写，π取3.14)"<< endl;
    cin >> choose;
    double S;
    if(choose='d')
    {
        int d;
        cout << "请输入直径"<< endl;
        cin >> d;
        S=(d/2)*(d/2)*pi;
      cout << "圆的面积是"<else if(choose='r')
    {
        int r;
        cin >> r;
        S=r*r*pi;
        cout << "圆的面积是"<else if(choose='c')
    {
        int c;
        cin >> c;
        int obj=c/6.2831852;
        S=obj*obj*pi;
        cout << "圆的面积是"<else
    {
        cout << "错误，请重新运行"<< endl;
    };
    return 0;
  }#include 
#define pi 3.1415926
#define p2 6.2831852
using namespace std;

int main(void){
    char choose;
    cout << "请输入要输入的数据类型"<< endl;
    cout << "直径输d,半径输r,周长输c(严格区分大小写，π取3.14)"<< endl;
    cin >> choose;
    double S;
    if(choose='d')
    {
        int d;
        cout << "请输入直径"<< endl;
        cin >> d;
        S=(d/2)*(d/2)*pi;
      cout << "圆的面积是"<else if(choose='r')
    {
        int r;
        cin >> r;
        S=r*r*pi;
        cout << "圆的面积是"<else if(choose='c')
    {
        int c;
        cin >> c;
        int obj=c/6.2831852;
        S=obj*obj*pi;
        cout << "圆的面积是"<else
    {
        cout << "错误，请重新运行"<< endl;
    };
    return 0;
  }

要不考虑switch语句试试

运行慢是什么慢，至少你这if比较也应该是两个等号吧

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