segmentation fault in for loop

[Rpog]

please could someone detect some kind of error in the code, because it never enters the loop for, because it doesnt printf, since i cant find the error, i was hoping someone could help me.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAXLINE 1024
  char *res 
  char line[MAXLINE]="blabla = job";
  char *vchar;
  int k,n;
  vchar=(char)malloc((sizeof (char))*100);
  res=fopen(argv[2], "r+");
  
  for(k=0, n=0; line[k]!='\0'; k++,n++ )
        {
            printf("this is the loop");
            if ((line[k]>='a' && line[k]<='z') ||(line[k]>='A' && line[k]<='Z'))
          {
            line[k]=vchar[n];
            printf("IF 1\n");
          }
            else 
          {
            if((line[k]>='a' && line[k]<='z') ||(line[k]>='A' && line[k]<='Z'))
              { 
                  printf("IF 2\n");
                 vchar[k]='\0';
            if(strstr(name,vchar))
              {
                printf("YET another IF\n");
                fprintf(res,"%s",corpo);
              }
            else
              {
                vchar[n]='\0';
                fprintf(res,"%s",vchar);
              }
              }
         } 

[Rpog]

i switched from

vchar=(char)malloc((sizeof (char))*100);

to

vchar=malloc((sizeof(char))*100);

and it didnt segmentation fault, sorry to waste space in the forum

[adrianxw]

You have other problems. For example, you create a pointer to res, but not the storage for res, thus your pointer is pointing to nothing. By itself, that wouæld probably kill you sooner or later, but you then go on to use it as the target for a call to fopen() which returns a FILE * not a char.

[incognito54]

the best way to find segmentationf fault is to use gsb and then run the program till it dumps the core... you see where it crashed and then you add breakpoints to lines that can be sensitive and run the program step by step and see what happens