When we are using a 2-D array of characters we are at liberty to either initialize the strings where we are declaring the array,or receive the string using scanf() fucntion.However when we are using an array of pointers we can not receive the strings from keyboard using scanf(). why?
#include<stdio.h>
int main()
{
char *names[6];
int i;
for(i=0;i<=5;i++)
{
printf("Enter name:");
scanf("%s",names[i]);
}
return 0;
Your code doesn't work because it invokes undefined behavior by storing strings into pointers which are not initialized to point to anything. You need to use malloc().
valgrind is a tool which would catch this sort of program for you, automatically.
char *names[6];
declares names as an array of pointers to char but does not allocate memory for elements of names. You need to allocate memory for each element before writing to it, otherwise it will invoke undefined behavior.
Try this:
for(i = 0; i <= 5; i++)
{
printf("Enter name:");
names[i] = malloc(SIZE); // SIZE is for length of string
if( names[i] != NULL)
scanf("%s", names[i]);
}
scanf does not allocate memory automatically, so you have to allocate a buffer for storing the input before calling scanf.
#include<stdio.h>
int main()
{
char *names[6];
int i;
for(i=0;i<=5;i++)
{
printf("Enter name:");
names[i]=(char *)malloc(256); // 256 is size of buffer
scanf("%s",names[i]);
}
return 0;
