Why can't my function take the user input?

Question

void patient_data(){    

    char name[10];
    int ID[4];
    int age;
    char history[100];
    float temp;
    int breath; 

    printf("enter patient data:\n");    

    scanf("name : %s\n", name);
    scanf("ID: %d\n",ID);
    scanf("age %d\n",&age);
    scanf("history: %s\n", history);
    scanf("temp: %f\n",&temp);
    scanf("breath: %s\n", breath);

    FILE *info;
    info = fopen("info.txt","a");   

    fscanf(info,"%s     %d  %d  %s  %f  %d",name, ID, &age, history, &temp,&breath);
}

this code is supposed to take user input for patient data and save it in a file that should be accessed later, but the scanf functions are not working.

any Idea on what might be the issue here?

This reads the data from the file, not from user input. If you wanted to take user input and then save it to a file, you would `scanf` it from the user and then `fprintf` it to the file. — nanofarad, Jun 07 '20 at 22:58
You open `info` for writing and then use a read function (fscanf) — M.M, Jun 07 '20 at 23:23

anastaciu · Answer 1 · 2020-06-09T15:28:29.657

Your scanf's are ill-formed, they should simply be:

scanf(" %9s", name); //<-- added buffer limit
scanf("%d",ID);
scanf("%d",&age);
scanf(" %99s", history); //<-- added buffer limit
scanf("%f",&temp);
scanf("%d", &breath);` // <-- corrected the specifier

If you want to print tags for the user to know what to input use printf or puts before every scanf.

Note that the last scanf has a specifier missmatch, it takes an integer but uses a string specifier.

Also note that the "%s" specifier is unsafe, you should use "%99s" for a 100 char container to avoid buffer overflow. The way you have it, it's no better than gets().

Finally the correct function to write to a file is fprintf.

fprintf(info,"%s     %d  %d  %s  %f  %d", name, ID, age, history, temp, breath);

Why can't my function take the user input?

1 Answers1