I want to create an array of strings Below is the program
char *s[6];
int n=6,i=0;
char str[10];
while(n--)
{
scanf("%s",str);
s[i]=str;
i++;
}
for(i=0;i<6;i++)
printf("%s\n",s[i]);
Six strings are accepted from the keyboard, but nothing is displayed on the output. Can anyone help me out here? Thanks!
s[i]=str;
You are assigning same str to all s. All strings would be same on printing. If last string is empty for some reason, all would be empty.
Moreover you should reset n to 5 before second loop.
while(n--)
{
scanf("%s",str);
if(i >= 6) break; /* 1. Can not go beyond 6 */
s[i]=malloc(strlen(str) + 1); /* 2. Allocate */
if(s[i]) strcpy(s[i], str); /* 3. Copy */
i++;
}
n = 5; /* 4. reset */
for(i=0;i<n;i++)
printf("%s\n",s[i]);
...
for(i = 0; i < n; i++) free(s[i]); /* 5. free */
char s[6][MAX_STRING_LENGTH], but you still need strcpy or read directly in s[i]
strdup would work for unix type systems (Make sure to free at end). But you must note at the same time that it not part of the ISO C standard itself and is a POSIX extension.The address of str is fixed. Thus in statement
s[i]=str;
each element of the array of character pointers s gets the same address. You coudl change the code snippet at least the following way
#include <string.h>
//...
#define N 6
//...
char s[N][10];
int n = N, i = 0;
char str[10];
while ( n-- )
{
scanf("%9s", str );
strcpy( s[i], str );
i++;
}
for( i = 0; i < N; i++ )
puts( s[i] );
The while loop would be better to write as a for loop
for ( i = 0; i < n; i++ )
{
scanf("%9s", str );
strcpy( s[i], str );
}
Also pay attention to that if your compiler supports Variable Length Arrays and the array s is a local variable of a function (for example of main) you could define it the following way
int n;
printf( "Enter the number of strings you are going to enter: " );
scanf( "%d", &n );
if ( n <= 0 ) n = N;
char s[n][10];
nis 0 at start of for loop. also all of your strings will point at the last one scanned..char *s[5];can hold five strings(char *).