在 C 中检索数组的用户输入

Question

Beginner programming including arrays and I'm having trouble just getting user input for the arrays. The printf functions I've included are just to check whether my arrays are working, the larger program I'm writing just needs to use these two arrays.

The input for the char array seems to work fine, I've tried a couple of different methods. However, the int array doesn't seem to work using the same diversity of methods I've used successfully with the char array. Not sure what I'm missing. Below is the code and the output when I run the program:

int main()
{

char grades[5]; // create array to store letter grades
int hours[5]; // array to store hours

puts("Please enter letter grades:"); // Input letter grades using fgets
fgets(grades, 5, stdin);

printf("Letter grade for course 3 is %c.\n", grades[2]);


int x = 0;

puts("Please enter course hours:\n");
for (x = 0; x < 5; x++)
{
    scanf("%d", &hours[x]);
}

printf("Course hours for course 2 are: %d.\n", hours[1]);

return 0;
}

Output of this code:

Please enter letter grades:
ABCDF <- user input
Letter grade for course 3 is C.
Please enter course hours:

Course hours for course 2 are: -858993460.
Press any key to continue . . .

Answer 1

fgets(grades, 5, stdin); captures ABCD of the input leaving F in the input stream. scanf("%d", &hours[x]); can't parse an int from F though it tries five times. Each failure leaves the F in the input stream.
Make buffers large enough for typical input.
Use fgets for all input. Parse with sscanf or others. Use the return of sscanf to make sure the parsing was successful.

#include <stdio.h>

int main( void)
{

    char grades[50] = ""; // create array to store letter grades
    char line[50] = "";
    int hours[5] =  { 0}; // array to store hours
    int result = 0;

    puts("Please enter letter grades:"); // Input letter grades using fgets
    fgets(grades, sizeof grades, stdin);

    printf("Letter grade for course 3 is %c.\n", grades[2]);


    int x = 0;

    for (x = 0; x < 5; x++)
    {
        do {
            printf("Please enter course %d hours:\n", x + 1);
            fgets ( line, sizeof line, stdin);
            result = sscanf( line, "%d", &hours[x]);
            if ( result == EOF) {
                printf ( "EOF\n");
                return 0;
            }
        } while ( result != 1);
    }

    printf("Course hours for course 2 are: %d.\n", hours[1]);

    return 0;
}