io - How can one flush input stream in C?

Question

I am not able to flush stdin here, is there a way to flush it? If not then how to make getchar() to take a character as input from user, instead of a " " left by scanf() in the input buffer??

#include "stdio.h"
#include "stdlib.h"

int main(int argc,char*argv[]) {
    FILE *fp;
    char another='y';
    struct emp {
        char name[40];
        int age;
        float bs;
    };
    struct emp e;
    if(argc!=2) {
        printf("please write 1 target file name
");
    }
    fp=fopen(argv[1],"wb");
    if(fp==NULL) {
        puts("cannot open file");
        exit(1);
    }
    while(another=='y') {
        printf("
Enter name,age and basic salary");
        scanf("%s %d %f",e.name,&e.age,&e.bs);
        fwrite(&e,sizeof(e),1,fp);

        printf("Add another record (Y/N)");
        fflush(stdin);
        another=getchar();
    }
    fclose(fp);
    return 0;
}

EDIT: updated code, still not working properly

#include "stdio.h"
#include "stdlib.h"

int main(int argc,char*argv[]) {
    FILE *fp;
    char another='y';
    struct emp {
        char name[40];
        int age;
        float bs;
    };
    struct emp e;
    unsigned int const BUF_SIZE = 1024;
    char buf[BUF_SIZE];

    if(argc!=2) {
        printf("please write 1 target file name
");
    }
    fp=fopen(argv[1],"wb");
    if(fp==NULL) {
        puts("cannot open file");
        exit(1);
    }
    while(another=='y') {
        printf("
Enter name,age and basic salary : ");
        fgets(buf, BUF_SIZE, stdin);
        sscanf(buf, "%s %d %f", e.name, &e.age, &e.bs);
        fwrite(&e,sizeof(e),1,fp);
        printf("Add another record (Y/N)");
        another=getchar();
    }
    fclose(fp);
    return 0;
}

Output:

dev@dev-laptop:~/Documents/c++_prac/google_int_prac$ ./a.out emp.dat

Enter name,age and basic salary : deovrat 45 23
Add another record (Y/N)y

Enter name,age and basic salary : Add another record (Y/N)y

Enter name,age and basic salary : Add another record (Y/N)

Answer 1

fflush(stdin) is undefined behaviour^(a). Instead, make scanf "eat" the newline:

scanf("%s %d %f
", e.name, &e.age, &e.bs);

Everyone else makes a good point about scanf being a bad choice. Instead, you should use fgets and sscanf:

const unsigned int BUF_SIZE = 1024;
char buf[BUF_SIZE];
fgets(buf, BUF_SIZE, stdin);
sscanf(buf, "%s %d %f", e.name, &e.age, &e.bs);

---

^(a) See, for example, C11 7.21.5.2 The fflush function:

int fflush(FILE *stream) - If stream points to an output stream or an update stream in which the most recent operation was not input, the fflush function causes any unwritten data for that stream to be delivered to the host environment to be written to the file; otherwise, the behavior is undefined.