Go through a 2 dimensional array in C

Question

I want to print a two dimensional array's value, one by one. But my code shows one item many times :(

#include<stdio.h>
#include<conio.h>

void main()
{
    char words[][5]={"Hiii","Hello"};
    int size;
    char *cp,*p;
    p=words;
    clrscr();
    printf("%p ",p);
    size=sizeof(words);
    printf("Size %d\n",size);
    for(cp=p;cp<(p+size);cp++)
        printf("%s ",cp);
    getch();
}

Expected o/p
Hiii
Hello

Unexpected o/p
Hiii
iii
ii
i

Hello
ello
llo
lo
o

Answer 1

First of all, the array words is laid out in memory like

Hiii\0Hello

Also, since cp is a pointer to char, the expression cp++ increments cp by exactly on byte. That's you're printing "Hiii", followed by "iii" then "ii" and "i". For correctness, cp++ should be changed to cp += 5.

Finally, the array is incorrectly sized. The length of "Hiii" is 5 and the length of "Hello" is 6, since there is an implicit null terminator \0 at the end of each string. So words should actually be declared as char words[][6]={"Hiii","Hello"};. This also means that cp should now be incremented by 6 each time.

With the corrections made, the for loop becomes

for(cp=p;cp<(p+size);cp+=6)
  printf("%s ",cp);

To make you life easier, since you're working with an array, you can make use of indices rather the relying on pointer arithmetic:

int strCount = size / 6; // since each element of words is 6 characters long
for(int i = 0; i < strCount; i++)
    printf("%s ", cp);