A problem

[Kerrons]

Hello everyone , i have started practicing c in codefoces and i can't get this code to work for the problem Problem - A - Codeforces

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


int max(char tab[], int taille)
{
    int c=0, indice_max=0;


    while(c < taille)
    {
        if(tab[c] > tab[indice_max])
            indice_max = c;
        c+=2;
    }


    return indice_max;
}


void echanger(char tab[], int x, int y)
{
    int tmp;


    tmp = tab[x];
    tab[x] = tab[y];
    tab[y] = tmp;
}
tri(char tab[], int taille)
{
    int indice_max;


    for(int taille; taille > 1 ; taille-=2)
    {
        indice_max = max(tab, taille);


        echanger(tab, taille-2, indice_max);
    }
}




int main()
{


 char mot[100]="";
 scanf("%s",&mot);
 tri(mot[100],strlen(mot));
 char ch="";
 for (int j=2;j<strlen(mot);j+=1)
{
  strcat(ch,mot[j]);
}
printf("%s",ch);
}

[laserlight]

How does it not work? For example, if there is a compile error, what is the error message? If there is some kind of logic error, describe the context and show the test input, expected output, and actual output.

[Kerrons]

For the problem's full description check the red link at the top of the thread.

[Salem]

Before you even run the code, make sure you've fixed all the warnings.

$ gcc -Wall foo.c
foo.c:32:1: warning: return type defaults to ‘int’ [-Wimplicit-int]
 tri(char tab[], int taille)
 ^
foo.c: In function ‘main’:
foo.c:54:8: warning: format ‘%s’ expects argument of type ‘char *’, but argument 2 has type ‘char (*)[100]’ [-Wformat=]
  scanf("%s",&mot);
        ^
foo.c:55:6: warning: passing argument 1 of ‘tri’ makes pointer from integer without a cast [-Wint-conversion]
  tri(mot[100],strlen(mot));
      ^
foo.c:32:1: note: expected ‘char *’ but argument is of type ‘char’
 tri(char tab[], int taille)
 ^
foo.c:56:10: warning: initialization makes integer from pointer without a cast [-Wint-conversion]
  char ch="";
          ^
foo.c:59:10: warning: passing argument 1 of ‘strcat’ makes pointer from integer without a cast [-Wint-conversion]
   strcat(ch,mot[j]);
          ^
In file included from foo.c:3:0:
/usr/include/string.h:133:14: note: expected ‘char * restrict’ but argument is of type ‘char’
 extern char *strcat (char *__restrict __dest, const char *__restrict __src)
              ^
foo.c:59:13: warning: passing argument 2 of ‘strcat’ makes pointer from integer without a cast [-Wint-conversion]
   strcat(ch,mot[j]);
             ^
In file included from foo.c:3:0:
/usr/include/string.h:133:14: note: expected ‘const char * restrict’ but argument is of type ‘char’
 extern char *strcat (char *__restrict __dest, const char *__restrict __src)
              ^
foo.c:61:8: warning: format ‘%s’ expects argument of type ‘char *’, but argument 2 has type ‘int’ [-Wformat=]
 printf("%s",ch);
        ^
foo.c: In function ‘tri’:
foo.c:44:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

It is not sufficient to just fix the errors.

[Kerrons]

i am new at c programming so actually i don't understand the meaning of the errors.

[Salem]

Well you should have stopped at the first warning you didn't understand and posted a question.
Rather than carrying on digging an ever deeper hole to climb out of.

> foo.c:32:1: warning: return type defaults to ‘int’ [-Wimplicit-int]
> tri(char tab[], int taille)
> ^
> foo.c: In function ‘tri’:
> foo.c:44:1: warning: control reaches end of non-void function [-Wreturn-type]
> }
Does tri return a value or not?
If you don't specify a return type, the compiler assumes you mean int (that's the first message)
Having assumed it returns int, it then complains you don't return a value.

The best thing from looking at the code would be to make it return void.


> foo.c:55:6: warning: passing argument 1 of ‘tri’ makes pointer from integer without a cast [-Wint-conversion]
> tri(mot[100],strlen(mot));
> ^
> foo.c:32:1: note: expected ‘char *’ but argument is of type ‘char’
> tri(char tab[], int taille)
> ^
To pass an array to a function, you just use the array name - ie, just mot.
The second output (the note: ) is there to remind you what the function expects.


Try those for starters, and think about what the other things might mean.