Triggering break keyword with string variable in c language

Question

I am a programming noob. I was working on the assignment on my own and i hit the wall right now and any help will be appreciated.

I made loop where i get input for names, rates and hours and if user type -1 it will break the loop and move on to the next loop. Everything is fine except if i type -1 for name it just doesn't break. I know the variable is string and -1 is integer and i just can't figure out what should i do to make this work.

here is part of my stupid code.

for (i = 0; i < size; i++)

{
    puts("\ntype name: (type -1 to quit) \n");
    scanf_s("%s", &name[i], 20);
    puts("\ntype hourly rate: (type -1 to quit) \n");
    scanf_s("%f", &rate[i]);
    puts("\ntype hours worked: (type -1 to quit) \n");
    scanf_s("%f", &hours[i]);
    //if break keyword needed.

    if (*name == -1 || rate[i] == -1 || hours[i] == -1)
    {
        break;
    }

Why `"-1"` in a string field? Why not just an empty string? `if (!strlen(name))` — Tibrogargan, Jul 15 '18 at 05:16
It is sadly a part of assignment, but thank you for teaching another function. — Young KIm, Jul 15 '18 at 05:19
You can not compare strings with ==, and you can not compare strings to numbers. Use atoi() to convert a string to integer, or use strcmp() with "-1" (string representation of -1). — linuxfan says Reinstate Monica, Jul 15 '18 at 05:20
@Tibrogargan [Why shouldn't I use atoi()?](https://stackoverflow.com/q/17710018/995714) — phuclv, Jul 15 '18 at 08:31

J...S · Answer 1 · 2018-07-15T06:09:11.203

You could use strcmp() like

scanf_s("%19s", name[i], 20);
if(strcmp(name[i], "-1")==0)
{
    break;
}

strcmp() compares the two strings and returns 0 if both are same.

Leading spaces are not a problem and will be ignored. So -1 will still be read as -1.

Otherwise you could first convert the string in name[i] to an integer and then see if the resultant number is -1. For that approach, see How to convert a string to integer in C?.

Also, if name[i] is a character array of size 20, instead of

scanf_s("%s", &name[i], 20);

you probably need

scanf_s("%19s", name[i], 20);

as name[i] itself is the address since array names decay to pointers to their first element in C.

See this and this.

Triggering break keyword with string variable in c language

1 Answers1