Thread: sorting a simple text file

I have a text file thats looks like this:

JWF 29
NTK 659
QCU 459
OHK 945
QLI 345

I want a program that will sort it by number highest to lowest by number to look like this:

JWF 29
QLI 345
QCU 459
NTK 659
OHK 945

The things that are constant are that the list will always be 5 items long, the characters will always be 3 characters long, and the input file will always be input.txt

I wrote this program that will read in all the elements in the text file and write them to another file:

Code:

# include <stdio.h>

int main(void)
{
    int score[5][5];
    int x;
    int z;
  
    FILE *outputfile;
    FILE *inputfile;
    
    outputfile = fopen("output.txt","w");
    inputfile = fopen("input.txt","r");
    
    if(inputfile==NULL)
    {
         printf("Error: can't find file 'input.txt' ");
         system("pause");
         return 1;
    }
    
   for(x=0;x<=4;x++)
   {
            for(z=0;z<=2;z++)
            {
                  fscanf(inputfile, " &#37;c", &score[x][z]);
            }
            
            fscanf(inputfile, "%d", &score[x][4]);
    }
    
    for(x=0;x<=4;x++)
    {
          for(z=0;z<=2;z++)
          {
              fprintf(outputfile,"%c",score[x][z]);
          }
          fprintf(outputfile," %d \n",score[x][4]);
    }
    
    return(0);
}

Somewhere in the middle I need to sort it by the numbers in score[0..4][4]

I'm so lost, because all of the columns must retain the same structure, while only moving positions as a whole.

If you don't want to swap the data around (and who does?) then you'll need to make an "extra" set of indices and sort those instead. That is, you might have an array order_to_print[5] -- order_to_print[0] would tell you which row to print first, order_to_print[1] would tell you which row to print second, etc.

Edit to add: and while your method of a 5x5 array of integers is ... correct ... it might be a good idea to look at structures (which will allow you to group characters and integers together into one "thing").