C Programming - Strings - Discussion

@Gourav.

The output of this program is False
This happens because if(str1==str2) compares the address of str1 and srt2 which is not the same.

Hence it swiches to else part and gives False as output.
You can instead use strcmp(str1,str2) or declare them as char *str1, *str2;

#include<stdio.h>
int main()
{
char str1[]="Hello";
char str2[]="Hello";
if ( str1==str2 )
printf("True");
else
printf("False");
}

What is the output? and please explain.

Nice explation @kavyashree

Clear Explanation @Nandita thank you.

@Nandita.

Nice explanation, thank you.

Output:

Enter a line of text. This is a sentence

Now,

for(i=strlen(sentence)-1; i >=0; i--)

=>for(i=strlen(This is a sentence)-1; i >=0; i--)
=>for(i=18-1; i >=0; i--)
=>for(i=17; i >=0; i--)

putchar(sentence[i]);

=> putchar(sentence[i]);
=> putchar(sentence[17]);
=> e

Similarly,

=>for(i=16; i >=0; i--)
putchar(sentence[i]);
=> putchar(sentence[i]);
=> putchar(sentence[16]);
=> c

Similarly,
i-- => sentence[i]=>sentence[15]=>n.
i-- => sentence[i]=>sentence[14]=>e.
i-- => sentence[i]=>sentence[13]=>t.
i-- => sentence[i]=>sentence[12]=>n.
i-- => sentence[i]=>sentence[11]=>e.
i-- => sentence[i]=>sentence[10]=>s.
i-- => sentence[i]=>sentence[9]=>
i-- => sentence[i]=>sentence[8]=>a.
i-- => sentence[i]=>sentence[7]=>
i-- => sentence[i]=>sentence[6]=>s.
i-- => sentence[i]=>sentence[5]=>i.
i-- => sentence[i]=>sentence[4]=>
i-- => sentence[i]=>sentence[3]=>s.
i-- => sentence[i]=>sentence[2]=>i.
i-- => sentence[i]=>sentence[1]=>h.
i-- => sentence[i]=>sentence[0]=>T.


So,The sentence will get printed in reverse order.

strlen function will give the length of input string including null character and strlen(sentence)-1 will point to last character.

But strlen (hello) means it prints only 5 not 6. How I points to the last element of the string. Please anyone explain?

Thanks kavyashree.

Nice explanation.

In for loop we initializing i with 1 less the length of the string, so i points to the last element of the string, and we printing each character and decrementing i by 1 which willl print the characters in revers order.