Question

我不知道我使用Visual Studio的代码有什么问题，它说我没有标识符，而且我不是100％知道这意味着我基本上必须为pow写一个新功能，而我不是很了解太多了，但是如果有人可以看一下我的代码，真的很有帮助，谢谢

// Programmer:     Your Name
// Date:           Date
// Program Name:   The name of the program
// Chapter:        Chapter # - Chapter name
// Description:    2 complete English sentences describing what the  program does,
//                 algorithm used, etc.
#define _CRT_SECURE_NO_WARNINGS // Disable warnings (and errors) when using non-secure versions of printf, scanf, strcpy, etc.
#include <stdio.h> // Needed for working with printf and scanf
#include <math.h>
#include <string.h>

int main(void)
{
    // Constant and Variable Declarations
    double power(double num, int power) {
        double result = 1;
        if (power > 0) {
            int i = 0;
            for (i = 0; i < power; i++) {
                result *= num;
            }
            return result;
        }
        else {
            if (power < 0) {
                power *= -1;
                int i = 0;
                for (i = 0; i < power; i++) {
                    result *= num;
                }
            }
            return 1 / result;
        }
    }
    int main(void)
    {
        double number;
        int p;
        printf("Enter a number to raise to a power : ");
        scanf("%lf", &number);
        printf("Enter the power to raise %.2lf to : ", number);
        scanf("%d", &p);
        printf("%.2f raised to the power of %d is : ", p);
        double result = power(number, p);
        double mathPow = pow(number, p);
        printf("\n%-20s%-20s\n", "My Function", "Pow() Function");
        printf("%-20.2f%-20.2f\n", result, mathPow);
        return 0;
    }
    // *** Your program goes here ***
    return 0;
} // end main()

Answer 1

您不能（或至少不应该）在C函数内部定义函数。

cc -Wall -Wshadow -Wwrite-strings -Wextra -Wconversion -std=c99 -pedantic -g `pkg-config --cflags glib-2.0`   -c -o test.o test.c
test.c:15:41: error: function definition is not allowed here
    double power(double num, int power) {
                                        ^
test.c:36:5: error: function definition is not allowed here
    {
    ^

您有两个main函数。 main是在程序运行时由操作系统运行的功能。您只需要一个。

还有其他一些问题...

test.c:41:52: warning: format specifies type 'double' but the argument has type 'int' [-Wformat]
    printf("%.2f raised to the power of %d is : ", p);
            ~~~~                                   ^
            %.2d
test.c:41:42: warning: more '%' conversions than data arguments [-Wformat]
    printf("%.2f raised to the power of %d is : ", p);

printf缺少参数。应该是...

printf("%.2f raised to the power of %d is : ", number, p);

使用这些修复程序可以正常工作。

您可以通过定义仅用于正数的第二个功能来DRY来power。

double power_positive(double num, int power) {
    int i = 0;
    double result = 1;
    for (i = 0; i < power; i++) {
        result *= num;
    }
    return result;
}

double power(double num, int power) {
    if (power < 0) {
        return 1 / power_positive(num, -power);
    }
    else {
        return power_positive(num, power);
    }
}

只是想知道我的代码C编程到底有什么问题

1 个答案: