#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <string.h>
#define FLUSH myFlush()
struct testInfo {
int grade;
char letterGrade;
char student[30];
};
void menuPrint(int);
void enterScores(struct testInfo **scores, int size);
void printScores(struct testInfo scores[], int size);
char getChoice();
void myFlush();
int main(void) {
struct testInfo *testScores = { 0 };
char userChoice;
int size = 0;
do {
system("clear");
menuPrint(1);
userChoice = getChoice();
switch (userChoice) {
case 'e': case 'E':
system("clear");
menuPrint(2);
printf("Please enter the number of test scores: ");
scanf_s("%d", &size); FLUSH;
testScores = (struct testInfo*)malloc(size * sizeof(struct testInfo));
if (!testScores) { //if there is an error in allocating the memory, exits program.
printf("\nA problem has occured with malloc.");
exit(EXIT_FAILURE);
}
else {
enterScores(&testScores, size);
}
system("pause");
break;
case 'p': case 'P':
printScores(testScores, size);
system("pause");
free(testScores);
break;
case 'l': case 'L':
system("pause");
break;
}
} while (userChoice != 'l' && userChoice != 'L');
return 0;
}//end main
I am trying to pass a dynamic structure to a function so the user can write the student's name and test score they got on a test. I've used Passing a Structure by reference to a function that will dynamically create and fill a array of structures as a reference to figure out how to pass the dynamic structure to the function, but when the user starts inputting, I can get through 1 loop before an exception is thrown saying "Access violation writing".
void enterScores(struct testInfo **scores, int size) {
int i;
char name[30];
for (i = 0; i < size; i++) {
printf("\nEnter student's name: ");
fgets(name, 30, stdin);
strcpy(scores[i]->student, name);
printf("\nEnter test score: ");
scanf_s("%i", &scores[i]->grade);
while (scores[i]->grade < 0 || scores[i]->grade > 120) {
printf("\nError in grade range (0-120), try again.");
printf("\nEnter test score: ");
}
//determines letter grade from test Score
if (scores[i]->grade > 90) {
scores[i]->letterGrade = 'A';
}
if (scores[i]->grade < 90 && scores[i]->grade >= 80) {
scores[i]->letterGrade = 'B';
}
if (scores[i]->grade < 80 && scores[i]->grade >= 70) {
scores[i]->letterGrade = 'C';
}
if (scores[i]->grade < 70 && scores[i]->grade >= 60) {
scores[i]->letterGrade = 'D';
}
if (scores[i]->grade < 60 && scores[i]->grade >= 0) {
scores[i]->letterGrade = 'F';
}
}
}//end enterScores
Your current enterScores
is accepting an array of pointers to struct testInfo
, but what is actually passed is a pointer to single pointer to struct testInfo
. This is treated as one-element array, and therefore accessing scores[1]
and further is invalid.
What you want seems:
Declaration of the function:
void enterScores(struct testInfo scores[], int size);
(use the same scheme as printScores
)
Call of the function:
enterScores(testScores, size);
(remove &
)
Definition of the function:
void enterScores(struct testInfo scores[], int size) {
int i;
char name[30];
for (i = 0; i < size; i++) {
printf("\nEnter student's name: ");
fgets(name, 30, stdin);
strcpy(scores[i].student, name);
printf("\nEnter test score: ");
scanf_s("%i", &scores[i].grade);
while (scores[i].grade < 0 || scores[i].grade > 120) {
printf("\nError in grade range (0-120), try again.");
printf("\nEnter test score: ");
}
//determines letter grade from test Score
if (scores[i].grade > 90) {
scores[i].letterGrade = 'A';
}
if (scores[i].grade < 90 && scores[i].grade >= 80) {
scores[i].letterGrade = 'B';
}
if (scores[i].grade < 80 && scores[i].grade >= 70) {
scores[i].letterGrade = 'C';
}
if (scores[i].grade < 70 && scores[i].grade >= 60) {
scores[i].letterGrade = 'D';
}
if (scores[i].grade < 60 && scores[i].grade >= 0) {
scores[i].letterGrade = 'F';
}
}
}//end enterScores
(change the argumen and replace ->
with .
)