c++中怎么限制while的次数，使下面这个进行第五次循环时判定失败

#include
#include
using namespace std;
int main()
{
srand((unsigned int)time(NULL));
int num = rand() % 100 + 1;
int a = 0;
cout << "请输入您所认为的数字" << endl;
cin >> a;
int c = 0;
while (c <= 5)
{
c = c + 1;
if(c<=5){
if (a > num)
{
cout << "错误，数字过大" << endl;

        }
        else if (a < num)
        {

            cout << "错误，数字偏小" << endl;

        }
        else
        {
            cout << "正确" << endl;
            break;
        }




    }

}
system("pause");
return 0;

}

修改如下，供参考：

#include<iostream>
#include<cstdlib>
#include<ctime>
using namespace std;
int main()
{
    srand((unsigned int)time(NULL));
    int num = rand() % 100 + 1;
    int a = 0;
    cout << "请输入您所认为的数字" << endl;
    cin >> a;
    int c = 0;
    while (c != 5-1)
    {
        //if (c <= 5) {
        if (a > num)
        {
            cout << "错误，数字过大" << endl;
        }
        else if (a < num)
        {
            cout << "错误，数字偏小" << endl;
        }
        else
        {
            cout << "正确" << endl;
            break;
        }
        c = c + 1;
        cin >> a;
        //}
    }
    system("pause");
    return 0;
}

你已经在while中写了判断了。不必在while循环体中再写一次if

while永远满足if的条件,如果不满足,不会走while

c初始值为0，while(c<=5)，这样实际会循环6次，把判断条件改为c<5，无论是while还是里面的if。

int main()
{
srand((unsigned int)time(NULL));
int num = rand() % 100 + 1;
int a = 0;
cout << "请输入您所认为的数字" << endl;
cin >> a;
int c = 0;
while (c < 5)
{
c = c + 1;
if (a > num)
{
  cout << "错误，数字过大，请重新输入" << endl;
  cin>>a;
  continue;
 }
 else if (a < num)
 {
            cout << "错误，数字偏小，请重新输入" << endl;
            cin>>a;
            continue;
        }
        else
        {
            cout << "正确" << endl;
            break;
        }
    }
}
system("pause");
return 0;
}

#include<iostream>
#include<cstdlib>
#include<ctime>
using namespace std;
int main()
{
    srand((unsigned int)time(NULL));
    int num = rand() % 100 + 1;
    int a = 0;
    cout << "请输入您所认为的数字" << endl;
    //cin >> a;
    int c = 0;
    while (c != 5)
    {
        cin >> a;
        if (a > num)
        {
            cout << "错误，数字过大" << endl;
        }
        else if (a < num)
        {
            cout << "错误，数字偏小" << endl;
        }
        else
        {
            cout << "正确" << endl;
            break;
        }
        c = c + 1;
    }
    system("pause");
    return 0;
}