Thread: Alphabetical Order HELP! dont understand what im doing wrong

I already have this code and I need help figuring out how to take in a .txt file and printing it out in alphabetical order. I dont understand how to use the strcmp function. Please help!

Code:

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

#define MAX_LENGTH 40

void sort(char names[][MAX_LENGTH], int size);
void print(char names[][MAX_LENGTH], int size);
int my_strcmp(const char* s1, const char* s2);
void swap(char names[][MAX_LENGTH], int i, int j);
void my_strcpy(char* s1, const char* s2);

int main() {
    
    char filename[MAX_LENGTH];
    FILE *fin;
    int i;
     
    // Get the name of the file and open it.
    printf("What file stores the input names?\n");
    scanf("%s", filename); 
    fin = fopen(filename,"r");
    
    // Find out the number of names.
    int n;
    fscanf(fin, "%d", &n);
    char names[n][MAX_LENGTH];
    
    // Read in all of the names.
    for (i=0; i<n; i++)
        fscanf(fin, "%s", names[i]);
    
    sort(names, n);
    printf("Here is the list of names:\n");
    print(names, n);
    
    fclose(fin);
    system("PAUSE");
    return 0;
}


void sort(char names[][MAX_LENGTH], int size) {

    int i,j;
    
    // How far we have to go in the array on each iteration.
    for (i=size-1; i>0; i--) 
    
        // Just swap any adjacent elements that are out of order.
        for (j=0; j<i; j++)
            if (my_strcmp(names[j], names[j+1]) > 0)
                swap(names, j, j+1);            
}     


void swap(char names[][MAX_LENGTH], int i, int j) {
    char temp[MAX_LENGTH];
    my_strcpy(temp, names[i]);
    my_strcpy(names[i], names[j]);
    my_strcpy(names[j], temp);     
}
     

void print(char names[][MAX_LENGTH], int size) {

    int i;
    for (i=0; i<size; i++)
        printf("%s\n", names[i]);
}     


int my_strcmp(const char* s1, const char* s2) {

  
}


void my_strcpy(char* s1, const char* s2) {
int i;

   for ( i = 0; ( s1[ i ] = s2[ i ] ) != '\0'; i++ ) {
      ;   
   } 
}

Isn't that what I am doing here?

Code:

    // Just swap any adjacent elements that are out of order.
        for (j=0; j<i; j++)
            if (my_strcmp(names[j], names[j+1]) > 0)
                swap(names, j, j+1);

Provided you had written my_strcmp, so that it returned something meaningful?

That's what I dont understand, in the books I'm reading the function doesn't have anything in it. I figured thats what the #include <string.h> is for.

Rewriting C libraries is one of the dumbest things you can do.

Use strcmp(). Unless your professor explicitly told you to write your own implementation.

Speaking of going over stuff, Matus, did you get your code back that I had sent you with many many many comments and a few changes, and a couple recommendations?

Actually..... Hold up, I didn't look at your insert function until now and it is funky.

Ok cool. I would insert alphabetically, if I were you. The nice thing about circular linked lists is you can scan through them bidirectionally with easy