c - 如何在此while循环C中将int更改为double

我正在使用这段代码计算输入的平方和立方，我添加了第三个选项来计算除以2的值，所以我不得不将结果从int改为double，但我认为我做得不对以下是我目前掌握的情况：

#include <stdio.h>
// Function prototypes int Square(int value); int Cube(int value);

int main ()
{
    /* variable definition: */
    int intValue, menuSelect,Results;
    double doubleValue, Resultsb;
    intValue = 1;
    doubleValue = intValue;
    // While a positive number
    while (intValue > 0)  {
        printf ("Enter a positive Integer\n: ");
        scanf("%d", &intValue);
        doubleValue=intValue;
        if (intValue > 0)  {
            printf ("Enter 1 to calculate Square, 2 to Calculate Cube, 3 to Shrink
                   value in half \n: ");
            scanf("%d", &menuSelect);
            if (menuSelect == 1)  {
                // Call the Square Function
                Results = Square(intValue);
                printf("Square of %d is %d\n",intValue,Results);
            }
            else if (menuSelect == 2)  {
                // Call the Cube function
                Results = Cube(intValue);
                printf("Cube of %d is %d\n",intValue,Results);
            }
            else if (menuSelect == 3) {
                Resultsb = Shrink(doubleValue);
                printf("%f shrunk in half is %f\n", doubleValue,Resultsb);
            }
            else
                printf("Invalid menu item, only 1, 2 or 3 is accepted\n");
        }
    }
    return 0;
}
/* function returning the Square of a number */
int Square(int value)
{
    return value*value;
}
/* function returning the Cube of a number */
int Cube(int value)
{     return value*value*value;
}
double Shrink(double value)
{   return value/2;
}

如果有人能告诉我我做错了什么，那就太棒了，谢谢！

最佳答案

在调用函数之前，需要该函数的原型否则，默认返回类型为int所以说：

int Square(int value);
int Cube(int value);
double Shrink(double value);

在main()之前，或将函数定义移到顶部。
您也不需要doubleValue变量将intValue传递给函数将根据原型自动转换它。
这是工作程序。

#include <stdio.h>
// Function prototypes
int Square(int value);
int Cube(int value);
double Shrink(double value);

int main ()
{
    /* variable definition: */
    int intValue, menuSelect,Results;
    double Resultsb;
    intValue = 1;
    // While a positive number
    while (intValue > 0)  {
        printf ("Enter a positive Integer\n: ");
        scanf("%d", &intValue);
        if (intValue > 0)  {
            printf ("Enter 1 to calculate Square, 2 to Calculate Cube, 3 to Shrink value in half \n: ");
            scanf("%d", &menuSelect);

            if (menuSelect == 1)  {
                // Call the Square Function
                Results = Square(intValue);
                printf("Square of %d is %d\n",intValue,Results);
            }
            else if (menuSelect == 2)  {
                // Call the Cube function
                Results = Cube(intValue);
                printf("Cube of %d is %d\n",intValue,Results);
            }
            else if (menuSelect == 3) {
                Resultsb = Shrink(intValue);
                printf("%d shrunk in half is %f\n", intValue,Resultsb);
            }
            else
                printf("Invalid menu item, only 1, 2 or 3 is accepted\n");
        }
    }
    return 0;
}
/* function returning the Square of a number */
int Square(int value)
{
    return value*value;
}
/* function returning the Cube of a number */
int Cube(int value)
{     return value*value*value;
}
double Shrink(double value)
{   return value/2;
}