I need help to this

[PoisonMind]

Here is my code

#include<stdio.h> 
#define MAXL 256 
 
// funcoes pos e inv 
 
int mystrlen(char *string) { // DEVOLVE TAMANHO DA STRING 
    int tamanho = 0;  
    while(*(string+tamanho)!='\0') { 
      tamanho++; 
    } 
    return tamanho; 
} 
 
char* inv(char* C) { // INVERTER 
    int length, i; 
    char *begin; // Apontador para o inicio da string 
    char *end; // Apontador para o fim da string 
    char temp;  
    length = mystrlen(C); // Chamada a função strlen que devolve o tamanho da string 
    begin = C;              
    end = C;             
    end += length-1;     
    for (i=0;i<length/2;i++) {         
        temp = *end; 
        *end = *begin; 
        *begin = temp; 
        begin++; 
        end--; 
    } 
    return C; 
} 
 
char* pos(char* C,char* S) { // PROCURAR C em S 
    int CAux = 0; int csize = mystrlen(C); 
    int SAux = 0; int ssize = mystrlen(S); 
    int howMany = 1; 
    char results[ssize];
    char* r = results; 
    int i;  
    for(i = 0;i < ssize; i++){ 
        if(C[CAux] == S[i]){ 
            SAux = i; 
            while((C[CAux] == S[SAux]) && (CAux < csize-1)){ 
                CAux++; 
                SAux++; 
                howMany++; 
                if(howMany == csize-1){ 
                    sprintf(results, " %d", i); 
                } 
            } 
            SAux = i + 1; 
            CAux = 0; 
            howMany = 0; 
        } 
    } 
    return r; 
} 
 
 
/* _-*_-*_-*_-*_-* MAIN *-_*-_*-_*-_*-_ */ 
 
int main(int argc, char *argv[]) {     
    char str[MAXL]; 
    char *r=str;     
    // declarar aqui outras variaveis, se necessario 
    char* compStr;
    char* res; 
    while(r!=NULL) { 
        r=fgets(str,MAXL,stdin); 
 
        // chamar a funcao pos() ou inv(), conforme o caso 
        if(argv[1][0] == 'p') { // pos() 
            compStr = argv[2];            
            res = pos(r, compStr); 
        }     E
        else if(argv[1][0] == 'i') { // inv()
            res = inv(r);
            //printf("%s\n", res); 
        } 
         
        // imprimir os resultados 
        printf("%s\n",res);         
    } 
    return 0; 
}

on running this program, if you do ./cadeias i: (inv function that reverses C)
you will able to write a string to returns the reverse.

ex: ./cadeias i (enter)
Pedro
out -> ordeP

if you do ./cadeias p anystring: (pos function that finds C in S)
you will be able to write a sting to find in "anystring" and returns the posicions that the sub string are.

ex: ./cadeias p PETER
E
out -> 2 4

but, its printing things like that: "pYS�����"

can you help me finding where is the problem???

[Salem]

> char results[ssize];
> char* r = results;
...
> return r;
You're returning a pointer to a local variable.
So when the function returns, the variable goes out of scope, the pointer is invalid, and the memory is trashed by doing something else.

Try something like this, where you pass in a pointer to where you want the result stored.

    char res[100];
...
   pos(r, compStr. res);

[PoisonMind]

res = pos(compStr, r); i forgot to rewrite on my code


I'm doing that because pos function recives 2 char pointers char * C and char * S

how can i turn this compatible?

[Salem]

Well typically, you would use malloc to allocate a variable amount of memory.

[PoisonMind]

NEW VERSION OF MY CODE.

#include<stdio.h> 
#define MAXL 256 
 
// funcoes pos e inv 
 
int mystrlen(char *string) { // My String Lenght - returns string lenght 
    int len = 0;  
    while(*(string+len)!='\0') { 
      len++; 
    } 
    return len; 
} 
 
char* inv(char* C) { // REVERSE C and returns C reversed 
    int length, i; 
    char *begin; 
    char *end; 
    char temp;  
    length = mystrlen(C); 
    begin = C;              
    end = C;             
    end += length-1;     
    for (i=0;i<length/2;i++) {         
        temp = *end; 
        *end = *begin; 
        *begin = temp; 
        begin++; 
        end--; 
    } 
    return C; 
} 
 
char* pos(char* C,char* S) { // FIND C in S and returns a pointer for a char that contains the positions where C is in S 
    int CAux = 0; int csize = mystrlen(C); 
    int SAux = 0; int ssize = mystrlen(S); 
    int howMany = 1; 
    char results[ssize];
    char* r = results; 
    int i;  
    for(i=0;i<ssize;i++){ 
        if(C[CAux] == S[i]){ 
            SAux = i; 
            while((C[CAux]==S[SAux]) && (CAux<(csize-1))){ 
                CAux++; 
                SAux++; 
                howMany++; 
                if(howMany == (csize-1)){ 
                    sprintf(results + mystrlen(results), " %d", i); 
                } 
            } 
            SAux = i + 1; 
            CAux = 0; 
            howMany = 0; 
        }
         
    } 
    return r; 
} 
 
 
/* _-*_-*_-*_-*_-* MAIN *-_*-_*-_*-_*-_ */ 
 
int main(int argc, char *argv[]) {     
    char str[MAXL]; 
    char *r=str;     
    // declarar aqui outras variaveis, se necessario (another var.) 
    char *compStr;
    char* res; 
    while(r!=NULL) { 
        r=fgets(str,MAXL,stdin);
 
        // chamar a funcao pos() ou inv(), conforme o caso (call pos() or inv()) 
        if(argv[1][0] == 'p') { // pos() 
            compStr = argv[2];            
            res = pos(compStr, r); 
        }     
        else if(argv[1][0] == 'i') { // inv()
            res = inv(r); 
        } 
         
        // imprimir os resultados (Print results) 
        printf("%s\n",res);         
    } 
    return 0; 
}

on running this program:

1 ____ "i"

if you do ./cadeias i: (inv function that reverses C)
you will able to write a string to return the reverse.

ex: ./cadeias i (enter)
Pedro
out -> ordeP

2 _____ "p"

if you do ./cadeias p anystring: (pos function that finds C in S)
you will be able to write a sting to find in "anystring" and returns the posicions that the sub string are.

ex: ./cadeias p PETER
E
out -> 2 4

but, its printing things like that: "pYS�����"

can you help me finding where is the problem???

[Salem]

Nope - I looks for malloc, couldn't see it.
Thanks for playing.

[phantomotap]

O_o

-_-

o_o

o_O

Bwahaha!

Did that really just happen? (*)

[Edit]
Responding to edited post:

If you want help you'll have to be more responsible with volunteer time.

If you don't understand what Salem has suggested feel free to ask, but posting different code with the exact same problem isn't going to win anyone over.

Try to employ what you've been told.
[/Edit]

This is now my favorite thread.

Soma

(*) It seems to me like he tried to hijack this thread not realizing it was his own.

[PoisonMind]

????? this is an help???

[rogster001]

You will get answers like that when you do not make any effort to revise a previous post, or ask new questions / try new things based on the information somebody has volunteered to you.

[PoisonMind]

sorry salem i dont see your post for malloc.

I tried this

char* pos(char* C,char* S) { // FIND C in S and returns a pointer for a char that contains the positions where C is in S 
    int CAux = 0; int csize = mystrlen(C); 
    int SAux = 0; int ssize = mystrlen(S); 
    int howMany = 1; 
    char results[ssize];
    char* r = malloc(sizeof(char)*1024); 
    int i;  
    for(i=0;i<ssize;i++){ 
        if(C[CAux] == S[i]){ 
            SAux = i; 
            while((C[CAux]==S[SAux]) && (CAux<(csize-1))){ 
                CAux++; 
                SAux++; 
                howMany++; 
                if(howMany == (csize-1)){   
                    sprintf(r + mystrlen(r), " %d", i);
                    printf("%s\n",r);     
                } 
            } 
            SAux = i + 1; 
            CAux = 0; 
            howMany = 0; 
        }
         
    }
    free(r); 
    return r; 
}

and gcc give me:

pedro@pedro:~/Documentos/AC/T2$ gcc -Wall -o cadeias cadeias.c
cadeias.c: Na função ‘pos’:
cadeias.c:38:2: aviso: implicit declaration of function ‘malloc’ [-Wimplicit-function-declaration]
cadeias.c:38:12: aviso: incompatible implicit declaration of built-in function ‘malloc’ [habilitado por padrão]
cadeias.c:58:2: aviso: implicit declaration of function ‘free’ [-Wimplicit-function-declaration]
cadeias.c:58:2: aviso: incompatible implicit declaration of built-in function ‘free’ [habilitado por padrão]

Am i using malloc in bad context???

[jimblumberg]

No you didn't include the required header file (stdlib.h).

Jim

[AndiPersti]

free(r); 
return r;

It's not very clever to free a pointer before returning it.

Bye, Andreas