How to write functions that use values from other functions - c

Question

I am a complete beginner at c so please give me advice that is as simple as possible.
I have two questions. How do you use scanf in a function with pointers because my program is not working at all.
Also, how do you write functions that uses values from another function. For example I have to write a function that asks for employee name, hours worked, and hourly rate. And then I have to write another function that uses that information to calculate gross pay and overtime pay.
This is the scanf code I wrote so far:
#include <stdio.h>
#include <stdlib.h>
int employeedata(char *ch, float *x, float *y)
{
printf("Enter your name:\n");
scanf_s("%s", &ch);
printf("Enter your hourly rate:\n");
scanf_s("%f", &x);
printf("Enter number of hours worked:\n");
//variables
scanf_s("%f", &y);
}
int main() {
float rate[5], hours[5];
float overtimerate = 1.5;
char name[5][20];
int loop;
//loop 5 times
for (loop = 0; loop < 5; loop++)
{
//call function
employeedata(name[loop], &rate[loop], &hours[loop]);
//use if to break out of loop after input if -1 is entered
if (strcmp(name, "-1") == 0)
break;
if (rate[loop] == -1)
break;
if (hours[loop] == -1)
break;
}
system("pause");
return 0;
}

Answer 1

You are passing pointer to a pointer in scanf function in line
scanf_s("%s", &ch);
But scanf requires pointers to buckets where you want the read values to be put. Hence the corrected code should be
scanf_s("%s", ch);
Same error in lines
scanf_s("%f", &x);
scanf_s("%f", &y);
which must be
scanf_s("%f", x);
scanf_s("%f", y);
Because x, y & ch themselves are pointers
More:
Here is the prototype for the scanf()
int scanf(const char *format_string, ...);
where "..." (ellipsis) refer to pointers to the buckets.

Answer 2

edit: here is an example for everything you wanted
#include <stdio.h>
#include <stdlib.h>
char *inputString(FILE* fp, size_t size) {
//The size is extended by the input with the value of the provisional
char *str;
int ch;
size_t len = 0;
str = realloc(NULL, sizeof(char)*size);//size is start size
if (!str)return str;
while (EOF != (ch = fgetc(fp)) && ch != '\n') {
str[len++] = ch;
if (len == size) {
str = realloc(str, sizeof(char)*(size += 16));
if (!str)return str;
}
}
str[len++] = '\0';
return realloc(str, sizeof(char)*len);
}
void CalcFunc(double hours, double rate, double* gross, double* otime);
int main(void) {
char *name;
double HoursWorked = 0, RatePerHour = 0, GroosPay =0, OverTime=0;
printf("input name: ");
name = inputString(stdin, 10);
printf("input hours worked: ");
scanf("%lf", &HoursWorked);
printf("input rate per hour: ");
scanf("%lf", &RatePerHour);
CalcFunc(HoursWorked, RatePerHour, &GroosPay, &OverTime);
printf("Name:%s\n", name);
printf("hours worked:%.2f\n", HoursWorked);
printf("rate per hour:%.2f\n", RatePerHour);
printf("over time:%.2f\n", OverTime);
printf("gross pay:%.2f\n", GroosPay);
free(name);
return 0;
}
void CalcFunc(double hours, double rate, double* gross, double* otime) {
//just an example for function
*otime = hours*2;
*gross = hours*rate*0.3;
return;
}