Question

嘿伙计......再来一次新手:)我正在组合一个计算三角形或正方形区域的程序，然后提示用户是否希望计算另一个。我已经得到了代码，它将计算任一形状的区域，但不会继续其余的代码。例如，选择方形，计算面积，然后返回到方形边的提示。我假设它永远是while循环，但不知道如何阻止循环无休止地继续。

继承我的代码：

 #include<stdio.h>
 #include<math.h>

 int main(void)

 {
     float sq_side, tri_base, tri_height, Area;
     char shape, cont = 'Y';

     printf("Please select the type of shape you desire to calculate the area for:\n");
     printf("                                                                     \n");
     printf("   Square = S                             Triangle = T               \n");
     printf("   -------                                    x                      \n");
     printf("   :     :                                   x x                     \n");
     printf("   :     :                                  x   x                    \n");
     printf("   -------                                 xxxxxxx                   \n");
     printf("                                                                     \n");
     printf("Please select either S or T:");
     scanf("%c", &shape);
     while (cont != 'n' && cont != 'N')

        if (shape == 'S' || shape == 's')
        {
            printf("What is the length of the sides of the square?:\n");
            scanf("%f", &sq_side);

            Area = pow(sq_side,2);

            printf("The area of the square is %.2f.\n", Area);
        }   

        else if (shape == 'T' || shape == 't')
        {
            printf("What is the length of the base of the triangle?:\n");
            scanf("%f", &tri_base);
            printf("What is the height of the triangle?:\n");
            scanf("%f", &tri_height);

            Area = 0.5 * tri_base * tri_height;

            printf("The area of the triangle is %.2f.\n", Area);
        }   

        else 
        {
        printf("Error:  You have select an incorrect option.");
        }

        printf("Do you wish to calculate a new shape?");
        fflush(stdin);
        scanf("%c", &cont);

     return(0);

 }

Answer 1

你缺少花括号。结果是只有if语句（包括else ifs链）实际上在循环体中。 printf（及更高版本）不是此复合语句的一部分。

 while (cont != 'n' && cont != 'N')
 {
    if (shape == 'S' || shape == 's')
    {
        printf("What is the length of the sides of the square?:\n");
        scanf("%f", &sq_side);

        Area = pow(sq_side,2);

        printf("The area of the square is %.2f.\n", Area);
    }   

    else if (shape == 'T' || shape == 't')
    {
        printf("What is the length of the base of the triangle?:\n");
        scanf("%f", &tri_base);
        printf("What is the height of the triangle?:\n");
        scanf("%f", &tri_height);

        Area = 0.5 * tri_base * tri_height;

        printf("The area of the triangle is %.2f.\n", Area);
    }   

    else 
    {
    printf("Error:  You have select an incorrect option.");
    }

    printf("Do you wish to calculate a new shape?");
    fflush(stdin);
    scanf("%c", &cont);
}

Answer 2

循环时没有括号。所以if elseif else块之外的代码没有被调用。

目前您的代码转换为

while (cont != 'n' && cont != 'N')
{
    if (shape == 'S' || shape == 's')
    {}
    else if (shape == 'T' || shape == 't')
    {}   
    else 
    {}
}

printf("Do you wish to calculate a new shape?");
fflush(stdin);
scanf("%c", &cont);

何时需要

while (cont != 'n' && cont != 'N')
{
    if (shape == 'S' || shape == 's')
    {}
    else if (shape == 'T' || shape == 't')
    {}   
    else 
    {}

    printf("Do you wish to calculate a new shape?");
    fflush(stdin);
    scanf("%c", &cont);
}

请记住，如果在控件结构中不包含花括号，它只会调用下一个语句，在您的情况下是一系列嵌套的if-else if语句。

希望它有所帮助 - Val

虽然循环帮助

2 个答案: