I need help with a really really simple code ...

[Izzy Me]

Im a little "noob" in c ... But a rather simple code is breaking my mind...

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



main()

{
int i;
char word[100];
char trocas[100];
FILE *fpin;
FILE *fpout;

fpin = fopen ("frases.txt", "r");
fpout = fopen("mistura.txt", "w");


if (fpin == NULL)
{
printf("Erro ao abrir o ficheiro.");
exit(1);
}


if(fpout == NULL)
{
printf("Erro ao abrir o ficheiro.");
exit(1);
}

//And i dont think fgetc should be the best option but i have very limited Knowledge in c
for(i=0;i<100;i++)
{
word[i]=fgetc(fpin);
}



//Im trying to save one array to another but also changing is index so when it appears in the final file its a little scrambled ...
for(i=0;i<100;i++)
{
trocas[i]=word[i+1];
trocas[i+1]=word[i];
}


fputs(trocas,fpout);

printf("OK\n");
fclose(fpin);
fclose(fpout);
system("PAUSE");
}



The purpose of this program is to read a txt file sending it to an array , then it sends to another but a little scrambled and then it sends to the final file ... name fpout ...

[Jikax]

for(i=0;i<100;i++) 
{
  trocas[i]=word[i+1];
  trocas[i+1]=word[i];
}

i think the probem is i+1 your loop runs to 99 because you array has elements from 0-99 that is ok. But the last element you read is 99+1=100, but this element does not exist.

And what are you trying to do exactly?

You are doing this:

trocas[0] = word[1];
trocas[1] = word[0];

Trocas[1] = word[2];
Trocas[2] = word[1];

Trocas[2] = word[3];
Trocas[3] = word[2];

etc...

as you can see you are writing double values. elements in Trocas are being overwritten. I guess that is not what you want?

[Gaminic]

Change the loop incrementer to "i += 2". It will not override (because 'i+1' is skipped) and it will only go to 98 causing no out-of-bounds access.

[Izzy Me]

im trying to put trocas[1] being word[2] and so on ... your write a sentence in a file like

"hello world"

im trying to put it into an array and trade it to another so it will end like this(example)

"llowe olrdw"


just and example

[Izzy Me]

the problem is when i execute the file ... The elements of the array "Trocas" should be the ones in array word but a little scrambled ... But its the same ... Not scrambled ... Both arrays are identical but i thought that for would scramble theirs index ...