Question

我在C代码中遇到上述错误。我也收到一个警告，说明整数转换的指针是不兼容的。赋值的目的是打印用户输入的整数的阶乘和两个近似阶乘。我可以获得如何修复错误的帮助吗？

以下是代码：

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

#define PI 3.141592653589793
#define e 2.71828
#define TRUE 1
#define FALSE 0

long long fact(int n);
double stirling1(int n);
double stirling2(int n);

/*--------------------------- main function -------------------------------
Purpose: The purpose of this program is to give the user the value of the 
factorial of the nonnegative integer the user inputs.
---------------------------------------------------------------------------*/

int main ()
{
char ch = 'y';
int flag, again;
int n;

again = TRUE;

while ( again == TRUE )
{
    printf("Please enter a nonnegative integer:"); //ask the user for the input
    flag = scanf("%d\n\n", &n);

    if ( flag != 1 ) //run this statement if the user inputs a noninteger
    {
        printf("Input must be an integer.");
        continue;
    }

    else if ( n < 0 ) //run this statement if the user inputs a negative integer
    {
        printf("The factorial is undefined...");
        continue;
    }

    else if ( n <= 14 ) //run this statement if the user inputs an integer less than or equal to 14
    {
        printf("Number     Factorial    Aprroximation          Aproxximation2\n------------------------------------------------------------------\n"); //prints the header for first table
        for ( n = 0; n <= 14; n++ )
            {
                ++n;
                printf("%d%1411lld%9e%9e\n", n, fact( n ), stirling1( n ), stirling2( n )); //calls functions to input factorials
            }
    }

    else //run this statement if the user inputs a number greater than 14
    {
        printf("Number   Approximation1         Approximation2\n-----------------------------------------------------\n"); //prints the header for second table
        for ( n = 0; n > 14; n++ )
        {
            ++n;
            printf("%3d%9e%e\n", n, stirling1( n ), stirling2( n )); //calls functions to input approximate factorials
        }
    }

    printf("Do you want to compute another factorial? (y/n):"); //ask user if they want another factorial of a different number
    scanf("%c\n", &ch);

    if (ch != 'y') 
        again = FALSE; //if user does not input 'y' then do not compute another factorial
}

printf( "**** Program Terminated ****" ); //ends program

}

long long fact( int n ) //function to find exact factorial
{
    fact *= n; //equation for exact factorial

    return fact; //return exact factorial to main
}

double stirling1( int n ) //function to find first approximate factorial
{
    n = pow( n, n ) * pow( e, -n ) * sqrt( 2 * PI * n); //equation to find    first approximate factorial

    return n; //return approximate factorial to main
}

double stirling2( int n ) //function to find second approximate factorial
{
    n = pow( n, n ) * pow( e, -n ) * sqrt( 2 * PI * n) * ( 1 + ( 1 / (12 * n) ));
    //equation to find second approximate factorial

    return n; //return approximate factorial to main
}

这是错误：

Lab_Assignment_4_Sarah_H.c:97:7: error: invalid operands to binary
  expression ('long long (int)' and 'int')
    fact *= n; //equation for exact factorial
    ~~~~ ^  ~
Lab_Assignment_4_Sarah_H.c:99:9: warning: incompatible pointer to integer
  conversion returning 'long long (int)' from a function with result type
  'long long' [-Wint-conversion]
    return fact; //return exact factorial to main
           ^~~~

Answer 1

您尝试将函数名称用作变量，在期望整数类型的上下文中使用它。

你要做的是再次调用函数，值为n-1，将结果乘以n，然后返回乘法的结果。

return n * fact(n-1);

还有一件丢失。如果你这样做，没有什么可以阻止递归函数调用。该函数将一直调用自己，直到你的堆栈空间不足为止。

需要的是基本情况，它会停止递归。

if (n <= 1) {
    return 1;
} else {
    return n * fact(n-1);
}

我在C代码中遇到错误：二进制表达式的操作数无效（＆＃39; long long（int）＆＃39; int＆＃39;）我不知道如何修复

1 个答案: