c++ - 打破 while 循环重复

Question

我想要实现的是用户输入一个值，然后输入一个测量值。然后将其放置为最小、最大或介于两者之间。保留输入了多少个值的计数。以及以米为单位的所有值的总和。

程序最初可以运行，但是当我输入换行符时，程序会重复同一行。我想要的是结束打印第 129 和 130 行的程序。这是我的代码。

int main()
{
    double var1; //the variable entered by the user
    double sum;  //the sum of calculations to convert into centimeters
    double total=0/100; //converts to meters
    int e=0; //will be used to count how many numbers were entered
    string measurment; //the users desired measurement input
    string centimeter = "cm";
    string meter = "m";         //these are used to compare the users measurement input
    string inch = "in";
    string foot = "ft";
    char d='t';//this will be used to break the loop (t is just the default)
    char a='a';
    char c='c';
    char m='m';//char a-f are used for a switch
    char i='i';
    char f='f';
    double small=20000;
    double large=0;
    double cm=1;
    double me=100;//centimeters
    double in=2.54; //centimeters
    double ft=12; //inches

    //the following code creates a break when the character is entered.
    while(d!='q')//break rule
    {
        if(false)
            break;

        cout<<"please enter a double and a unit of measurement."<<'\n';
        cin >>var1>>measurment;
        e++;

        // the following portion of code sets the char for the switch which
        // which will be used in the following code. it will also perform the
        // the math which will calculate between distances.

        if (measurment==centimeter)
        {
            a=c;
            sum=var1*cm;
        }
        else if (measurment==meter)
        {
            a=m;
            sum=var1*me;
        }
        else if (measurment==inch)
        {
            a=i;
            sum=var1*in;
        }
        else if (measurment==foot)
        {
            a=f;
            sum=(var1*ft)*in;
        }
        else
        {
        cout<<"I am sorry. But, that is not a valid measurement for this program."<<'\n';
        }

        //the following code places the number entered into either
        //smallest largest or in between.

        if (sum<small)
        {
            small=sum;
            total+=sum;
            switch(a){
        case'c':
            cout<<small/cm<<centimeter<<" is the smallest measurement so far."<<'\n';
            break;
        case'm':
            cout<<small/me<<meter<<" is the smallest measurement so far."<<'\n';
            break;
        case'i':
            cout<<small/in<<inch<<" is the smallest measurement so far."<<'\n';
            break;
        case'f':
            cout<<(small/in)/ft<<foot<<" is the smallest measurement so far."<<'\n';
            break;
            }
        }
        else if (sum>large)
        {
            large=sum;
            total+=sum;
            switch(a){
        case'c':
            cout<<large/cm<<centimeter<<" is the largest measurement so far."<<'\n';
            break;
        case'm':
            cout<<large/me<<meter<<" is the largest measurement so far."<<'\n';
            break;
        case'i':
            cout<<large/in<<inch<<" is the largest measurement so far."<<'\n';
            break;
        case'f':
            cout<<(large/in)/ft<<foot<<" is the largest measurement so far."<<'\n';
            break;
            }
        }
        else if(sum>small&&sum<large)
        {
            total+=sum;
        switch(a){
        case'c':
            cout<<var1<<centimeter<<" is neither the longest or shortest measurement."<<'\n';
            break;
        case'm':
            cout<<var1<<meter<<" is neither the longest or shortest measurement."<<'\n';
            break;
        case'i':
            cout<<var1<<inch<<" is neither the longest or shortest measurement."<<'\n';
            break;
        case'f':
            cout<<var1<<foot<<" is neither the longest or shortest measurement."<<'\n';
            break;
            }
        }
    }
    //after the break, this should be printed to screen
    cout<<"Of a total of "<<e<<" entries. "<<small<<meter<<" is the smallest length."<<'\n';
    cout<<"And "<<large<<meter<<" is the largest length. "<<total<<meter<<" is the total length."<<'\n';

    return 0;
}

如果代码太长，我们深表歉意。我不太确定你需要什么。我检查了许多帖子和网站并尝试了不同的中断代码但无济于事。我卡住了。

Answer 1

也许我遗漏了一些明显的东西，但打破 while 循环的正确方法是使条件失败。中断用于 FOR 循环，因为它们可以是非条件循环。无需跳出 while 循环，您只需创建变量

d ='q'

您想在哪里休息一下。请注意，中断仍然有效以中断 switch 语句，因此如果您需要，请将这些中断保留在那里。

对于任何拼写错误或者如果我遗漏了一个明显的问题，我很抱歉，我是移动的，可能遗漏了什么