Thread: String manupulation

Hi to all, I have that string "prog=0.64155436" and I want to manipulate it until it will be like "64.15%".

I've written a small code that works:

Code:

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

char *f (char *);

int main (void) {
        char str[] = "prog=0.64155436";
        printf ("%s \n", f (str));
        return (0);
        system("PAUSE");
}

char *f (char *s) {
        float f;
        char *p = (char *) malloc (sizeof (s));
        if (strstr (s, "prog="))
                        s = s + 5;
        f = atof (s);
        f = f * 100;
        sprintf (p, "%2.2f%%", f);
        return (p);
        
        
}

This works but it's not wat I was looking for, it was only a "try".

The REAL program it is the seguent (it uses the same funcion I created before) :

Code:

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

char *f (char *);

int main(void) {
  char done[100];  
  char *stato;
  FILE *file;  

  file = fopen("state.sah", "r"); 
  /* open a text file for reading */

  if(file==NULL) {
    printf("Seti@Home ha finito di elaborare la WorkUnit.\n");
    return 1;
  }
  else {
        
    while(fgets(done, 100, file)!=NULL) { 
    
        if(strstr(done,"prog=0.")) { printf("%s",done);
        printf ("%s \n", f (done)); }
        
       }

    fclose(file);
    system ("PAUSE");
    return 0;
  }
}

char *f (char *s) {
        float f;
        char *p = (char *) malloc (sizeof (s));
        if (strstr (s, "prog="))
                        s = s + 5;
        f = atof (s);
        f = f * 100;
        sprintf (p, "%2.2f%%", f);
        return (p);  
        
}

It looks in a file for the string I want and trys to modify it BUT it doesnt work because the output is :

prog=0.64155436
229339200.00%

and not

prog=0.64155436
64.15%

Thanx to everyone

Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h> /* required for atof */

void f(char *s) { /* instead of returning now just modifies s */
        float f;        /* notice there is no memory allocation this time */
        char *p;
        if (strstr (s, "prog=")) { /* your old program continued */
            p = s + 5;                  /* processing even when this */
            f = atof(p);                /* condition was false. */
            f = f * 100.0;
            sprintf(p, "%2.2f%%", f);
        }
}

int main()
{
    char s[] = "prog=0.64155436";
    
    f(s); /*no return we have to call it on a seperate line */
    printf("%s\n",s);
    return 0;
}

try that one on for size. the main is just for testing.

if (strstr (s, "prog="))

seems to fail....if i compile it, it says only press a key to continue..

anyway I will look at it better later thanx for your help

Originally Posted by BianConiglio

seems to fail....if i compile it, it says only press a key to continue..

anyway I will look at it better later thanx for your help

...okay...did you even read the code?

f(done)
should be
& f(done)
.....

I see you are trying to make a meter or something of how many seti units you have done, so I looked at the source code for a seti plugin to gkrellm, a program in linux. they did something like this

Code:

if(strcmp(string, "prog=") == 0) {
     sscanf(string, "prog=%lf", &somevar);
}

Of course it wasn't exactly like that being they used gtk type variables, strncmp, etc. If you want to look at the full code, you can download it at http://xavier.serpaggi.free.fr/seti/ but keep in mind most of the code deals with gtk.

ok it works, i forgot to include #include <stdlib.h>


(comments r in italian, sorry about that)

Code:

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

/* AGGIUNGENDO L'HEADER "STDLIB.H" FUNZIONA!!!
   Nel file stdlib.h viene dichiarato che la funzione "atof" restituisce un 
   double. Se non includiamo "stdlib.h" la funzione restituisce un double, ma 
   il main lo tratta come intero e quando lo stampo con la printf otteniamo un 
   valore errato */ 


int main(void) {
  
  char *tmp;        /* l'ho aggiunto io. Punta alla stringa in questione */
  char done[100];  
  char *stato;
  FILE *file;  
  double valore_perc; /* qui mettiamo il valore convertito in double */

  file = fopen("state.sah", "r"); 
  /* open a text file for reading */

  if(file==NULL) {
    printf("Seti@Home ha finito di elaborare la WorkUnit.\n");
    printf("Ora verra' scaricata una nuova WorkUnit.\n");
    return 1;
  }
  
  else {
        
    while(fgets(done, 100, file)!=NULL) { 
    
      if(tmp=strstr(done,"prog=")) { 
                  /* adesso tmp punta alla riga cercata */ 
                  
                   tmp=tmp + 5;     /* avanziamo il puntatore di 5 caratteri */
                   valore_perc=(double)atof(tmp); /* convertiamo in double */
                   valore_perc = valore_perc * 100;
                   printf("Percentuale completata : %2.2f%%\n\n",valore_perc); /* stampiamo il double */
                   break; /* usciamo dal while */ 
                  }
        
       }

    fclose(file);
    system("PAUSE");
        return 0;
  }
}