passing a string from one variable to another

hello, im trying to write a program that involves me needing to be able to arrange a bunch of names in a specific order that have been scanned from a file.

the exact order is determined by a function i wrote that compares a bunch of numerical values as show:

Code:

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void sort(double ppg[999], int numPlayers) {
  int y, x;
                                              // These keep it within range of datafile
    for (x = numPlayers - 1; x > 0; x = x - 1)
      for (y = 0; y < x; y = y + 1)
        if (ppg[y] < ppg[y+1])          // Compare size of integers
          swap(&ppg[y], &ppg[y+1]);
  }

void swap(double *a, double *b) {

  double temp;
  temp = *a;
  *a = *b;
  *b = temp;

}

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this code just compares two numbers and swaps them based on which is greater. however, a lot of the data i have to swap is strings of first names, last names etc..

so i was wondering if anyone knows how i could transfer the string in one variable into a second variable (to basically get the same effect as switching numbers)

i tried this:

Code:

---

void charswap(char *c[20], char *d[20]) {

  char temp[20];
  temp = *c;
  *c = *d;
  *d = temp;

}

---

but i got an error and i dont think strings can simply be set to equal a different variable to swap them the same way as a number would.

so does anyone know how to pass a string from one variable to another?

Code:

---

void charswap(char c[20], char d[20])
{
  char temp[20];
  strcpy(temp, c);
  strcpy(c, d);
  strcpy(d, temp);
}

---

hmmm, it makes a lot of sense. i updated it to:

Code:

---

void swap(double *a, double *b) {

  double temp;
  temp = *a;
  *a = *b;
  *b = temp;

}

void charswap(char c[20], char d[20])
{
  char temp[20];
  strcpy(temp, c);
  strcpy(c, d);
  strcpy(d, temp);
}

//-------------------------------------------------------------
// Function that will compare which variable is larger than the
// others and swap if true
//-------------------------------------------------------------

void sort(double ppg[999], int numPlayers, int games_played[999], int goals[999], int assissts[999],
  int points[999], char first_names[999], char last_names[999], char team_name[999], char position [999]) {
  int y, x;
                                              // These keep it within range of datafile
    for (x = numPlayers - 1; x > 0; x = x - 1)
      for (y = 0; y < x; y = y + 1)
        if (ppg[y] < ppg[y+1])          // Compare size of integers
          swap(&ppg[y], &ppg[y+1]);
          swap(&games_played[y], &games_played[y+1]);
          swap(&goals[y], &goals[y+1]);
          swap(&assissts[y], &assissts[y+1]);
          swap(&points[y], &points[y+1]);
          charswap(first_names[y], first_names[y+1]);
          charswap(last_names[y], last_names[y+1]);
          charswap(team_name[y], team_name[y+1]);
          charswap(position[y], position[y+1]);
  }

---

and then i go to call on it with this:

Code:

---

sort(ppg, numPlayers, points, goals, assissts, games_played, first_names, last_names, team_name, position);

---

but i get about 12 different error messages saying

passing argument 1 of charswap makes poitner from integer without a cast

and

passing argument 7/8/9 of sort from incompatible pointer type

i tried playing around with the functions like adding pointers to the charswap function but it didnt change anything

Code:

---

void charswap(char *c, char *d)



charswap(&first_names[y], &first_names[y+1]);

---

Your code had an index array in it, why not sort with that?

Code:

---

/*
Daniel Sedin VAN L 73 38
Steven Stamkos TBL C 72 43
Henrik Sedin VAN C 73 18
Martin StLouis TBL R 72 26
Corey Perry ANA R 72 39
Alex Ovechkin WSH L 73 29
Henrik Zetterberg DET L 73 21
Jonathan Toews CHI C 70 30
Anze Kopitar LAK C 73 25
Jarome Iginla CGY R 75 33
Patrick Sharp CHI L 71 34
Brad Richards DAL C 62 25
Teemu Selanne ANA R 63 22
Sidney Crosby PIT C 41 32


*/


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

#define MAX 14

void sort(int index[MAX], char fname[][22], int key);

int main(void) {

  int i = 0, j, got, len, index[MAX];
  char fname[MAX][22];
  char lname[MAX][22];
  char team[MAX][4];
  char plays[MAX];
  int  data[MAX][2];
 

  FILE *fp;

  printf("\n\n");
  if((fp=fopen("team.dat","r")) == NULL) {
    printf("Error opening data file\n");
    return 0;
  }

  while(1) { //giving fscanf() it's own line
    got = fscanf(fp,"%s %s %s %c %d %d", fname[i],lname[i],team[i],&plays[i],&data[i][0],&data[i][1]);
    if(got < 6)
      break;
 
    index[i] = i;  //you're building an index array at the same time? Good!   
    ++i; //welcome to C! :)    = i + 1;
   
  }
  //i has just counted the number of names in the array, so it can be used:

  printf("\n\n");
  for (j = 0; j < i; j++) {  //start with 0 not 1
    printf("%s %s %s %c %d %d\n",fname[j],lname[j],team[j],plays[j],data[j][0],data[j][1]);
  }

  sort(index, fname,1);
  printf("\n\n");
  for (j = 0; j < MAX; j++) {  //start with 0
    i = index[j];   
    printf("%11s  %-11s %4s  %c  %2d  %2d\n",fname[i],lname[i],team[i],plays[i],data[i][0],data[i][1]);
  }


  fclose(fp);
  printf("\n\n\t\t\t    press enter when ready");
  (void) getchar();
  return 0;
}
void sort(int index[MAX], char fname[][22], int key) {
  int i, j, temp;
   
  if(key==1) { //sort by first name
    /* This is substitution sort - similar to
    bubble sort, but slightly faster
    */
    for(i=0;i<MAX-1;i++) {
      for(j=i+1;j<MAX;j++) {
        /*compare strings i with j, using the index numbers
          no actual data is swapped out, with this index sort
        */

        if(strcmp(fname[index[i]], fname[index[j]]) > 0) {
          temp = index[i];
          index[i] = index[j];
          index[j] = temp;
        }
      }
    }
  }
  else if(key == 2) {
    //etc.
  }
}

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