我的代码给了我一个分段错误

Question

In my code I get a segmentation fault every time I try to run it. I have tried to comment out the majority of the code and only leave the initialize function and function call in the code so I believe that the segmentation fault is due to that function. However I do not know how to fix the error after trying for a while. I am including all of the code in case there is something from another function that is causing the fault and I am incorrect.

#include <stdio.h>
#include <string.h>
// function prototypes
void initialize(int* one, int* two, char* ch);
void getHoursRate(double* pRate, double* hrs);
double payCheck(double rate, double hours);
void printCheck(double rate, double hours, double amount);
void funcOne(int* pOne, int pTwo);
void nextChar(char* ch);

int main()
{
    int x, y;
    char z;
    double rate, hours;
    double amount;
    int* one = 0;
    int* two = 0;
    char* ch = NULL;
    double* pRate = 0;
    double* hrs = 0;
    
    // call initialize here...
    initialize(one, two, ch);
    printf("After initialization: x = %d, y = %d, z = %c\n", *one, *two, *ch);

    //call getHoursRate here...
    getHoursRate(pRate, hrs);
    rate = *pRate;
    hours = *hrs;
    //call payCheck here...
    amount = payCheck(rate, hours);
    //call printCheck here...
    printCheck(rate, hours, amount);

    x = 35;
    y = 20;
    printf("Before calling funcOne: x = %d, y = %d\n", x, y);
    //call funcOne with x & y here...
    funcOne(&x, y);
    printf("After funcOne: x = %d\n", *one);
    
    z = 'B';
    printf("Before nextChar z = %c\n", z);
    //nextChar with z here...
    nextChar(ch);
    printf("After nextChar: z = %c\n", *ch);
    
    return 0;
}
void initialize(int* one, int* two, char* ch){
    one = 0;
    two = 0;
    strcpy(ch, "~");
}
void getHoursRate(double* rate, double* hours){
    printf("Enter hours worked: ");
    scanf("%lf", hours);
    printf("Enter pay rate: ");
    scanf("%lf", rate);
    
}
double payCheck(double rate, double hours){
    double amount = 0;
    
    if (hours > 40){
        amount += 40 * rate;
        amount += (hours - 40) * rate * 1.5;
        return amount;
    }
    else{
        amount += 40 * rate;
        return amount;
    }
}
void printCheck(double rate, double hours, double amount){
    printf("Hours worked: %lf\nPay Rate: %lf\nThis week's salary: %lf\n", hours, rate, amount);
}
void funcOne(int* pOne, int pTwo){
    int temp;
    printf("Enter an integer: ");
    scanf("%d", &temp);
    *pOne = (*pOne * 2) + pTwo - temp;
}
void nextChar(char* ch){
    ch++;
}

Answer 1

You misunderstand the way variables are passed by reference, look at this fixed version :

#include <stdio.h>
#include <string.h>
// function prototypes

void initialize(int* one, int* two, char* ch);
void getHoursRate(double* pRate, double* hrs);
double payCheck(double rate, double hours);
void printCheck(double rate, double hours, double amount);
void funcOne(int* pOne, int pTwo);
void nextChar(char* ch);

int main()
{
    int x, y;
    char z;
    double rate, hours;
    double amount;
    int one = 0; // ==== Variable must not be declared as pointers
    int two = 0; // ==== They becomes pointers when you pass them
    char ch = 0; // ==== to the function,
    double pRate = 0;
    double hrs = 0;
    
    // call initialize here...
    initialize(&one, &two, &ch); //<======= FIX HERE
    printf("After initialization: x = %d, y = %d, z = %c\n", one, two, ch);

    //call getHoursRate here...
    getHoursRate(&pRate, &hrs); //<======= FIX HERE
    rate = pRate;
    hours = hrs;
    //call payCheck here...
    amount = payCheck(rate, hours);
    //call printCheck here...
    printCheck(rate, hours, amount);
   
    x = 35;
    y = 20;
    printf("Before calling funcOne: x = %d, y = %d\n", x, y);
    //call funcOne with x & y here...
    funcOne(&x, y);
    printf("After funcOne: x = %d\n", one);
    
    z = 'B';
    printf("Before nextChar z = %c\n", z);
    //nextChar with z here...
    nextChar(&ch);
    printf("After nextChar: z = %c\n", ch);
    
    return 0;
}
void initialize(int* one, int* two, char* ch){
    one = 0;
    two = 0;
    if (ch) *ch = '~'; //<======= FIX HERE
}
void getHoursRate(double* rate, double* hours){
    printf("Enter hours worked: ");
    scanf("%lf", hours);
    printf("Enter pay rate: ");
    scanf("%lf", rate);
    
}
double payCheck(double rate, double hours){
    double amount = 0;
    
    if (hours > 40){
        amount += 40 * rate;
        amount += (hours - 40) * rate * 1.5;
        return amount;
    }
    else{
        amount += 40 * rate;
        return amount;
    }
}
void printCheck(double rate, double hours, double amount){
    printf("Hours worked: %lf\nPay Rate: %lf\nThis week's salary: %lf\n", hours, rate, amount);
}
void funcOne(int* pOne, int pTwo){
    int temp;
    printf("Enter an integer: ");
    scanf("%d", &temp);
    if (pOne) *pOne = (*pOne * 2) + pTwo - temp;
}
void nextChar(char* ch){
    ch++;
}

Answer 2

You never actually allocate memory for one and two so they have space to hold integer data, they're just null pointers. If your declare them as int so there's memory for the value (and use them accordingly), you should be halfway there.