C Programming - Pointers - Discussion

I executed this and I got option c.

In gcc compiler, this program is crashed because *x=x[5] (x[5] is not allocated memory ). Am i right?

Actual code should be this, otherwise, an internal error will occur.

#include<stdio.h>
#include<string.h>
int main()
{
int i, n;
char *x = (char *)malloc(10*sizeof(char));
strcpy(x,"Alice");
n = strlen(x);//value of the n is 5
*x = x[n];//it copied the x[5] value('\0') to its base location so now string becomes " lice"
for(i=0; i<=n; i++)
{
printf("%s ", x);
x++;
}
printf("\n", x);
return 0;
}
now for i =0 printf will print from base location lets say 2000->" lice"
now for i=1 printf will print from 2001 upto null occur and so on->" lice ice ce e.

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

int main()
{
int i, n;
char *x="Alice";
n = strlen(x);
// *x = x[n];// this line introduce run time error, if you run on linux plateform.without this output will be{Alice lice ice ce e};
for(i=0; i<=n; i++)
{
printf("%s ", x);
x++;
}
printf("\n", x);
return 0;
}

o/p={Alice lice ice ce e};

Guys, please explain What is the last printf("\n", x) doing here?

But it is pointer to string constant which cannot be modified if it can be modified in turboC then its correct otherwise its an error.

Thanks for the explanation.

The question itself wrong or you need to add one more option for answer as "Undefined behaviour".

As I said above, In Linux, it throws "Segmentation fault" because of "*x = x[n];". It is correct since we are trying to change the string stored in read only memory. So what we have to do is create the memory which is not read only (In heap or in stack frame) as shown below

Solution: To avoid "Segmentation fault"

1.In heap:
char *x = (char *)malloc(10*sizeof(char));
strcpy(x,"Alice"); // copy in allocated mem
n = strlen(x);
*x = x[n];

2. In stack frame: Create char array & make the pointer to point the char array.
char *x;
char s[]="Alice";
x = s;
n = strlen(x);
*x = x[n];

In Linux, it throws "Segmentation fault" because of "*x = x[n];". It is correct since we are trying to change string constant.

Guys tell me in a simple way.