C Programming - Strings - Discussion

@GAURAV.

In *str also the NULL char is added.

For e.g: We undergo to find the length of string

char *str="BALAJI";
int length;
while(*str!='\0')
{
length++;
str++;
}
return(length);

In the above program, it clearly shows that only after detecting the '\0' on *str, the while() condition gets terminates, Hence the NULL char will be default. Don't confuse with Sizeof(). Statement is in both cases the '\0' will be ADDED at the end of the string "Sanjay" is TRUE.

I think there is typo in the second statement:

2: p is a non-const pointer pointing to a non-const string, whereas a is a const pointer pointing to a non-const pointer.

'a' can be considered a constant pointer, pointing to a non-const STRING, not POINTER.

Actually 'a' has type char[7] here, so in reality it is not a pointer, not even constant.

On the other hand, 'p' has type char*, so it is a pointer.

@All.

The program is to swap the first alphabet of the two strings. Can anyone tell the mistake?


#include<stdio.h>
int main(int argc, char* argv[])
{
char *c;
char *c1;
char *temp;
c=argv[1];
c1=argv[2];
temp[0]=c[0];
c[0]=c1[0];
c1[0]=temp[0];
printf("%s",c);
printf("%s",c1);
return 0;
}

yeah! i believe that option 3 is wrong because when we declare

char a[]={"girish"};

the entire array is initialised! hence i believe v cannot change the individual element.if v can really change then wt wl b the output for the following?

char a[]={"giri"};
printf("%c",a[2]);

We can chnage the individual characters in a string but not the whole string at a time...eg:
#include<stdio.h>
int main()
{
char str[] ="Visual";
*(str+2)='K';
printf("%s",str);
return 0;
}
similarle,to change other characters ,we can put some other value.

I think option C is correct. Because in char *p="Sanjay". Pointer p is in stack but that pointer pointing string 'Sanjay" is store in read-only text section. So it is a const string. That too char a[]="Sanjay" in that statement a is not a const pointer. So I think option C is correct.

@Ronil.

I agree with your comment. NULL character will not added at the end of second array string. Because array of string by default added NULL character at the end of string.

For eg:

*str1="GAURAV";
*str2[]="GAURAV";

sizeof (str1) = 6;
sizeof (str2) = 7;

Depending on compiler first option(2) may or may not be correct.

In turbo C it stores string pointed by pointer during initialization in data section whereas in gcc its in code section which is read only memory!

In first statement the character pointer p stores the address of the string "Sanjay".
The second statement specifies the space for Sanjay characters be allocated and that the name of location is a[].

Option 2 is wrong. Because p is a no constant pointer but it is pointing to the constant string (that string will be stored in the data segment in read only memory location).