Basic C help using arrays and for loops - c

Question

#include "stdafx.h"
#include "stdio.h"
#include <string.h>
void main() {
int Results[8];
int i = 0;
int max = 0;
int maxindex;
printf("Enter the results of your 7 leavin cert subjects: ");
do {
printf("\nSubject %d: ", i + 1);
scanf_s("%d", Results);
i++;
} while (i < 7);
for (i < 7; Results[i] > 0; i++)
if (Results[i] > max)
max = Results[i];
printf("The best grade is %d", max);
}
Hello, so basically I'm trying to print out the largest number(Best result) by using a for loop. However it keeps telling me the that the best result is 0.
Does anybody know what I'm doing wrong. Any help would be greatly appreciated.

Answer 1

There are 2 major problems in your code:
You read all numbers into Results[0] with the scanf_s("%d", Results);. You should instead write:
if (scanf_s("%d", &Results[i]) != 1) {
/* not a number, handle the error */
}
The second loop is incorrect: for (i < 7; Results[i] > 0; i++) has multiple issues. Write instead for (i = 0; i < 7; i++)
And smaller ones too:
#include "stdio.h" should be written #include <stdio.h>
#include "stdafx.h" is not used, and so can be removed - regardless, it should be written as #include <stdafx.h> if it were to be used.
The Results array has size 8, but you only use 7 slots.
main should have prototype int main(void) or int main(int argc, char *argv[]) or equivalent.
favor idiomatic for (i = 0; i < 7; i++) loops over error prone do / while loops.
use braces for a non trivial loop body.
Here is a simpler and better version:
#include <stdio.h>
#include <string.h>
int main(void) {
int Results[7];
int i, n, max;
printf("Enter the results of your 7 leavin cert subjects: ");
for (i = 0; i < 7; i++) {
printf("\nSubject %d: ", i + 1);
if (scanf_s("%d", &Results[i]) != 1) {
printf("invalid number\n");
exit(1);
}
}
for (n = i, max = 0, i = 0; i < n; i++) {
if (Results[i] > max)
max = Results[i];
}
printf("The best grade is %d\n", max);
return 0;
}