Using toupper with a structure in C

Question

What I am trying to do is to have the user input their information. Like state for example. I need to process this state abbreviation and output it as capital letters. I'm confused at how to do that because I am using structures. When I use what I am using below it tells me they are incompatible and it doesn't work. What should I do differently. I've tried pretty much everything. This is in C.

for (i = 0; i < 3 != '\0'; i++) {
    people[i].state = toupper(people[i].state);
}

`toupper()` works on one character at a time. It's hard to be sure because you haven't given the definition of your structure, but it looks like you're trying to apply it to a whole string. — John Bollinger, Feb 21 '17 at 18:18
@SouravGhosh The fanciest way to check if `i` is less than `3` I've seen so far. — Eugene Sh., Feb 21 '17 at 18:20
@EugeneSh. True, but I still suspect that wasn't the intent of that code. Ouch. — Andrew Henle, Feb 21 '17 at 18:22
For future questions, not that *Using `toupper()` with a structure* has no reason to be something special, `toupper()` takes a character and returns the *upper*case of it and that's all. It doesn't care where did the character come from. — Iharob Al Asimi, Feb 21 '17 at 18:33

Vlad from Moscow · Answer 1 · 2017-02-21T18:25:14.190

4

It seems you mean the following

for ( i = 0; i < 3; i++ )
{
    for ( char *p = people[i].state; *p; ++p ) *p = toupper( ( unsigned char )*p );
}

Or if you have a single object of the structure type then something like

for ( i = 0; i < 3; i++ )
{
    people.state[i] = toupper( ( unsigned char )people.state[i] );
}

or even

for ( i = 0; i < 3 && people.state[i] != '\0'; i++ )
{
    people.state[i] = toupper( ( unsigned char )people.state[i] );
}

edited Feb 21 '17 at 18:25

answered Feb 21 '17 at 18:17

Vlad from Moscow

301,070
26
186
335

2

@J.Piquard It is not standard C function. – Vlad from Moscow Feb 21 '17 at 18:26
@J.Piquard Ref: [strupr() and strlwr() in string.h part are of the ANSI standard?](http://stackoverflow.com/q/26327812/2410359) – chux - Reinstate Monica Feb 21 '17 at 21:11
When I put any of these in it gives me an error that says [Error]: incompatible types in assignment – Drew Feb 22 '17 at 02:18
@Drew What are the types of people and state? – Vlad from Moscow Feb 22 '17 at 08:46

@vladfromMoscow They are a type of character in a structure. I need to output it as two capital letters.

 
    #include 
    #include 

     struct info
     {
     char full_name[35];
     char address [50];
     char city [25];
     char state [3];
     long int zip_code;
     int age;
     }

    int main()
    {
 
     for (i = 0; i < 3; ++i) 
       {
         people[i].state = toupper(people[i].state);
      }

– Drew Feb 23 '17 at 22:51

Using toupper with a structure in C

1 Answers1