为什么我的.c文件无法识别我的头文件？ 2个错误，XCode

Question

我的标题文件：

#ifndef __FRACTION_H__

#define __FRACTION_H__

struct fraction{
    int wholeNumber;
    int numerator;
    int denominator;
};

struct fraction fractionCreate(int numerator, int denominator);
struct fraction fractionAdd(struct fraction a, struct fraction b);
struct fraction fractionSubtract(struct fraction a, struct fraction b);
struct fraction fractionMultiply(struct fraction a, struct fraction b);
struct fraction fractionDivide(struct fraction a, struct fraction b);
void fractionPrint(struct fraction f);

#endif

我在.c文件中遇到的2个错误是：

Undefined symbols for architecture x86_64: "_main", referenced from:
implicit entry/start for main executable
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

我的.c文件

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

struct fraction fractionCreate(int numerator, int denominator)
{
    struct fraction result;
    result.wholeNumber = 0;
    if (denominator == 0)
    {
        result.numerator = 0;
        result.denominator = 0;
    }
    else
    {
        if (numerator*denominator <0)
        {

            int tempNumerator = fabs(numerator);
            int tempDenominator = fabs(denominator);
            int temp = 0;
            while(tempDenominator != 0)
            {
                temp = tempDenominator;
                tempDenominator = tempNumerator%tempDenominator;
                tempNumerator = temp;
            }
            int GCD = tempNumerator;

            numerator = fabs(numerator);
            denominator = fabs(denominator);
            //Num is larger than denom
            if(numerator>=denominator)
            {
                //whole number
                if(numerator%denominator == 0)
                {
                    result.wholeNumber = (numerator/denominator)*-1;
                    result.numerator = 1;
                    result.denominator = 1;
                }
                //mixed number
                else
                {
                    result.wholeNumber = ((numerator - (numerator%denominator)) /denominator)*-1;
                    numerator = (numerator%denominator);
                    if (numerator%GCD ==0 && denominator%GCD ==0)
                    {
                        result.numerator = numerator/GCD;
                        result.denominator= denominator/GCD;
                    }
                    else
                    {
                        result.numerator = numerator;
                        result.denominator = denominator;
                    }
                }
            }

            //simple fraction
            else
            {
                if (numerator%GCD ==0 && denominator%GCD ==0)
                {
                    result.numerator = (numerator/GCD)*-1;
                    result.denominator= denominator/GCD;
                }
                else
                {
                    result.numerator = numerator*-1;
                    result.denominator = denominator;
                }
            }
        }

        else if (numerator*denominator > 0)
        {
            int tempNumerator = fabs(numerator);
            int tempDenominator = fabs(denominator);
            int temp = 0;
            while(tempDenominator != 0)
            {
                temp = tempDenominator;
                tempDenominator = tempNumerator%tempDenominator;
                tempNumerator = temp;
            }
            int GCD = tempNumerator;
            numerator = fabs(numerator);
            denominator = fabs(denominator);

            //Num is larger than denom
            if(numerator>=denominator)
            {
                //whole number
                if(numerator%denominator == 0)
                {
                    result.wholeNumber = numerator/denominator;
                    result.numerator = 1;
                    result.denominator = 1;
                }
                //mixed number
                else
                {
                    result.wholeNumber = (numerator - (numerator%denominator)) /denominator;
                    numerator = (numerator%denominator);
                    if (numerator%GCD ==0 && denominator%GCD ==0)
                    {
                        result.numerator = numerator/GCD;
                        result.denominator= denominator/GCD;
                    }
                    else
                    {
                        result.numerator = numerator;
                        result.denominator = denominator;
                    }
                }
            }

            //simple fraction
            else
            {
                if (numerator%GCD ==0 && denominator%GCD ==0)
                {
                    result.numerator = numerator/GCD;
                    result.denominator= denominator/GCD;
                }
                else
                {
                    result.numerator = numerator;
                    result.denominator = denominator;
                }
            }
        }
    }
    return result;
}

void fractionPrint(struct fraction f)
{
    if (f.numerator == 0 && f.denominator == 0)
    {
        printf("Divide by zero!\n");
    }
    else if(f.numerator ==0 && f.denominator !=0)
    {
        printf("0\n");
    }
    else
    {
        // There IS a whole number
        if (f.wholeNumber !=0)
        {
            //ONLY whole number
            if (f.numerator == 1 && f.denominator ==1 )
            {
                printf("%d\n", f.wholeNumber);
            }
            //Mixed number
            else
            {
                printf("%d %d/%d\n", f.wholeNumber, f.numerator, f.denominator);
            }
        }
        //fraction only
        else
        {
            printf("%d/%d\n", f.numerator, f.denominator);
        }
    }

}




struct fraction fractionAdd(struct fraction a, struct fraction b)
{
    struct fraction result;

    //If whole number exists
    if(a.wholeNumber!=0)
    {
        if (a.numerator ==1 && a.denominator ==1)
        {
            a.numerator =0;
        }
    }
    else if (b.wholeNumber!=0)
    {
        if (b.numerator ==1 && b.denominator ==1)
        {
            b.numerator =0;
        }
    }
    //If the numerator of a is 1 and denom is 1, then make it 0
    //If the numerator of b is 1 and deom is 1, then make it 0

    //Open up the mixed fraction
    a.numerator = (a.wholeNumber*a.denominator) + a.numerator;
    b.numerator = (b.wholeNumber*b.denominator) + b.numerator;

    //If the denominators equal
    if (a.denominator == b.denominator)
    {
        result.numerator = a.numerator + b.numerator;
        result.denominator = b.denominator;
        result = fractionCreate(result.numerator, result.denominator);
        return result;
    }
    else if (a.denominator == 0 && b.denominator == 0)
    {
    }
    //If the denominator is not equal,
    else if (a.denominator != b.denominator)
    {
        int LCM;
        int temp =0;
        //only use the absolute values when finding the GCD
        int tempDenominatorA = fabs(a.denominator);
        int tempDenominatorB = fabs(b.denominator);

        while(tempDenominatorB!=0)
        {
            temp = tempDenominatorB;
            tempDenominatorB = tempDenominatorA%tempDenominatorB;
            tempDenominatorA = temp;
        }
        int GCD = tempDenominatorA;
        LCM = fabs(a.denominator*b.denominator)/GCD;

        //then multiply each denominator and numerator by a number that will make it the LCM
        int multiplyA, multiplyB;
        multiplyA = LCM/fabs(a.denominator);
        multiplyB = LCM/fabs(b.denominator);
        a.numerator = a.numerator*multiplyA;
        b.numerator = b.numerator*multiplyB;

        result.numerator = a.numerator + b.numerator;
        result.denominator = LCM;

        result = fractionCreate(result.numerator, result.denominator);

        return result;

    }

    return result;
}

struct fraction fractionSubtract(struct fraction a, struct fraction b)
{
    struct fraction result;

    //If whole number exists
    if(a.wholeNumber!=0)
    {
        if (a.numerator ==1 && a.denominator ==1)
        {
            a.numerator =0;
        }
    }
    else if (b.wholeNumber!=0)
    {
        if (b.numerator ==1 && b.denominator ==1)
        {
            b.numerator =0;
        }
    }
    //If the numerator of a is 1 and denom is 1, then make it 0
    //If the numerator of b is 1 and deom is 1, then make it 0

    //Open up the mixed fraction
    a.numerator = (a.wholeNumber*a.denominator) + a.numerator;
    b.numerator = (b.wholeNumber*b.denominator) + b.numerator;
    a.wholeNumber = 0;
    b.wholeNumber = 0;

    //If the denominators equal
    if (a.denominator == b.denominator)
    {
        result.numerator = a.numerator - b.numerator;
        result.denominator = b.denominator;
        result = fractionCreate(result.numerator, result.denominator);
        return result;
    }
    else if (a.denominator == 0 && b.denominator == 0)
    {
    }
    //If the denominator is not equal,
    else if (a.denominator != b.denominator)
    {
        int LCM;
        int temp =0;
        //only use the absolute values when finding the GCD
        int tempDenominatorA = fabs(a.denominator);
        int tempDenominatorB = fabs(b.denominator);

        while(tempDenominatorB!=0)
        {
            temp = tempDenominatorB;
            tempDenominatorB = tempDenominatorA%tempDenominatorB;
            tempDenominatorA = temp;
        }
        int GCD = tempDenominatorA;
        LCM = fabs(a.denominator*b.denominator)/GCD;

        //then multiply each denominator and numerator by a number that will make it the LCM
        int multiplyA, multiplyB;
        multiplyA = LCM/fabs(a.denominator);
        multiplyB = LCM/fabs(b.denominator);
        a.numerator = a.numerator*multiplyA;
        b.numerator = b.numerator*multiplyB;

        result.numerator = a.numerator - b.numerator;
        result.denominator = LCM;

        result = fractionCreate(result.numerator, result.denominator);

        return result;

    }

    return result;
}

struct fraction fractionMultiply(struct fraction a, struct fraction b)
{
    struct fraction result;
    //If whole number exists
    if(a.wholeNumber!=0)
    {
        if (a.numerator ==1 && a.denominator ==1)
        {
            a.numerator =0;
        }
    }
    else if (b.wholeNumber!=0)
    {
        if (b.numerator ==1 && b.denominator ==1)
        {
            b.numerator =0;
        }
    }
    //If the numerator of a is 1 and denom is 1, then make it 0
    //If the numerator of b is 1 and deom is 1, then make it 0

    //Open up the mixed fraction
    a.numerator = (a.wholeNumber*a.denominator) + a.numerator;
    b.numerator = (b.wholeNumber*b.denominator) + b.numerator;

    a.wholeNumber = 0;
    b.wholeNumber = 0;

    result.numerator = a.numerator*b.numerator;
    result.denominator = a.denominator*b.denominator;

    result = fractionCreate(result.numerator, result.denominator);

    return result;
}

struct fraction fractionDivide(struct fraction a, struct fraction b)
{
    struct fraction result;
    //If whole number exists
    if(a.wholeNumber!=0)
    {
        if (a.numerator ==1 && a.denominator ==1)
        {
            a.numerator =0;
        }
    }
    else if (b.wholeNumber!=0)
    {
        if (b.numerator ==1 && b.denominator ==1)
        {
            b.numerator =0;
        }
    }
    //If the numerator of a is 1 and denom is 1, then make it 0
    //If the numerator of b is 1 and deom is 1, then make it 0

    //Open up the mixed fraction
    a.numerator = (a.wholeNumber*a.denominator) + a.numerator;
    b.numerator = (b.wholeNumber*b.denominator) + b.numerator;

    a.wholeNumber = 0;
    b.wholeNumber = 0;

    result.numerator = a.numerator*b.denominator;
    result.denominator = a.denominator*b.numerator;

    result = fractionCreate(result.numerator, result.denominator);

    return result;
}

Answer 1

你.c文件缺少main（）

gcc或任何其他编译器首先在程序中查找main（）（。c文件）

在我看来，你错过了.c文件中的main（）

尝试在.c文件中添加main（）并按照您想要的顺序调用main函数内的其他函数