Output using fprintf

#include <stdio.h>
#include <stdlib.h>

int main()
{
    int n, i, number;
    char subject[30];
    FILE *fp;

    printf("How many subjects? ");
    scanf("%d", &n);
    getchar();

    if((fp = fopen("input.txt", "w")) == NULL)
    {
        printf("Error opening file.\n");
        exit(1);
    }

    for(i = 0; i < n; i++)
    {
        printf("Enter the name of subject %d: ", i+1);
        gets(subject);
        printf("Enter the marks of subject %d: ", i+1);
        scanf("%d", &number);
        getchar();

        fprintf(fp, "%s %d\n", subject, number);
    }

    fclose(fp);

    return 0;

}