How can I avoid prompting the user multiple times for input? - c

Question

I am creating a simple program which asks for user input in one function mark and then passes the input values to a second function characters for validation.
#include <stdio.h>
void marks(float *mark1, float *mark2, float *mark3);
void characters(float mark1, mark2, float mark3);
void marks(float *mark1, float *mark2, float *mark3) {
float firstMark, secMark, thirdMark;
printf("Enter mark1, mark2, and mark3: ");
scanf("%f,%f,%f", mark1, mark2, mark3);
while (mark1 < 0 || mark2 < 0 || mark3 < 0) {
printf("Error, marks can't be less than zero \n");
printf("Enter mark1, mark2, and mark3: ");
scanf("%f,%f,%f", mark1, mark2, mark3);
firstMark = *mark1;
secMark = *mark2;
thirdMark = *mark3;
}
}
void characters(float mark1, float mark2, float mark3) {
marks(&mark1, &mark2, &mark3);
if (mark1 < 50 || mark2 < 50 || mark3 < 50) {
printf("Really Bad! You have failed. \n");
}
else if (mark1 > 50 && mark2 > 50 && mark3 > 50) {
printf("You have passed. \n");
}
else {
printf("ERROR! \n");
}
}
int main(void) {
int i;
float mark1, mark2, mark3;
printf("Grade list \n");
marks(&mark1, &mark2, &mark3);
characters(mark1, mark2, mark3);
}
The problem is in characters when I call the mark it asks for user input, but I only want the program to ask user to enter marks in main.
How can I call marks in characters without the program asking for data input, so that I can use it's parameters to calculate values?

Answer 1

If you do not want to ask the user for the input twice, remove the second call to marks. The input has been collected for characters by main through calling marks, and passed through the three parameters; there is no need to call it the second time.
This will fix your problem:
void characters(float mark1, float mark2, float mark3) {
// No second call to marks
if (mark1 < 50 || mark2 < 50 || mark3 < 50) {
...
}
...
}