如何在C中将全名转换为书目格式名称？

Question

I want to know how to convert, for example, this string:

"Barack Obama" to "OBAMA, Barack".

Ie, to bibliographic format, like when someone writes a book/article. But I want to know how to convert any kind of name in this format, it can be 2 names (as the case before) or 3, 4, 5... n names, for example:

Lionel Andrés Blablabla Soccer Player Messi

This name would be: MESSI, Lionel Andrés Blablabla Soccer Player.

I know how to do it if I know how much names the full name will have, but I want to know how I can do it for a full name that I don't know how many names it will have.

Here is what I've got so far (working only for 6 names in the example below):

char nome[30][100];
int i, j;

for(i = 0; i < 6; i++)
    scanf("%s", nome[i]);
for(j = 5; j > 4; j--)
    printf("%s,", strupr(nome[j]));
for(i = 0; i <= 4; i++)
    printf("%s ", nome[i]);

Answer 1

If the format is relatively simple (you seem to indicate so with your comment "any kind of name in this format"), you can use the following approach:

1. Use strrchr() to locate the last space in the string. Obviously, characters beyond that point constitute the surname.
2. Therefore characters before that point constitute all names that are not part of the surname.
3. So you simply print out the last name, a comma and space, then the earlier part of the string.

Now, granted, there are all sorts of edge cases that you may have to handle if your input strings aren't so nicely formatted, things like trailing spaces, surnames that consist of more than one word, and so on.

---

In terms of actual code, the following program would be a good starting point:

#include <stdio.h>
#include <string.h>
#include <ctype.h>

int main(void) {
    static char buffer[1000];

    while (1) {
        // Get line from user.

        printf ("\nEnter name> ");
        if (fgets(buffer, sizeof(buffer), stdin) == NULL) {
            printf("\n*** End of file, stopping.\n");
            return 0;
        }

        // Remove any trailing newline.

        if ((*buffer != '\0') && (buffer[strlen(buffer) - 1] == '\n'))
            buffer[strlen(buffer) - 1] = '\0';

        // Find last space. If none, output as is.

        char *lastSpace = strrchr(buffer, ' ');

        if (lastSpace == NULL) {
            printf ("        --> %s\n", buffer);
            continue;
        }

        // Otherwise separate, capitalise surname and output all.

        *lastSpace++ = '\0';

        for (char *surchar = lastSpace; *surchar != '\0'; surchar++)
            *surchar = toupper(*surchar);

        printf ("        --> %s, %s\n", lastSpace, buffer);
    }

    return 0;
}

A sample run of this is shown below:

Enter name> bob
        --> bob

Enter name> allan
        --> allan

Enter name> Barack Obama
        --> OBAMA, Barack

Enter name> Lionel Andres Blablabla Soccer Player Messi
        --> MESSI, Lionel Andres Blablabla Soccer Player

Enter name> <CTRL-D pressed>
*** End of file, stopping.