18.   What is the difference between "printf(...)" and "sprintf(...)"?
Ans:
sprintf(...) writes data to the character array whereas printf(...) writes data to the standard output device.

Ex - 1: what is the output of the following code?
              #include<stdio.h>
               void main()
                {
                 printf("%d",printf(" hello world "));
                 }
                 a) 13, b) hello world 13, c) hello world, d) error
Ans: b

Ex - 2: what will print out?
main()
{
        char *p1=“name”;
        char *p2;
        p2=(char*)malloc(20);
        memset (p2, 0, 20);
        while(*p2++ = *p1++);
        printf(“%sn”,p2);
}
Ans:empty string.