Keep characters in an array - c

Question

I want to do a program that ask to the user to give one character, then enter... until he wants to stop by pressing enter and no caracters.
Then, the program will say: "you gave the caracters ...."
for example:
give the caracter 1: k + enter
give the caracter 2: l + enter
give the caracter 3: just enter ('\n')
result: You gave the caracters: kl
My code doesnet work because when i just press enter, nothing happen. Here is the code:
#include <stdio.h>
#define N 1000
int main() {
int i = 0;
int j = 0;
char str[N];
while (str[i] != '\n') {
printf("element number str[%d] : ", i);
scanf("%s", &str[i]);
i++;
}
printf("The string is: ");
while (j < i) {
printf("%s", str[j]);
j += 1;
}
return 0;
}

Answer 1

You can do it with c = getchar(); or c = fgetc(stdin) function:
#include <stdio.h>
#define N 1000
int
main ()
{
int i = 0;
int j = 0;
int c;
char str[N];
while (1)
{
c = fgetc(stdin); // or c = getchar();
if ( (c != EOF) && (c != 0x0A ) ) // 0x0A = 'nl' character
{
str[i] = (char) c;
printf ("element number str[%d]=%c \n", i, str[i++] );
}
else
{
str[i] = 0;
break;
}
}
printf ("The string is: %s", str);
return 0;
}
OUTPUT:
This is my string!
element number str[1]=T
element number str[2]=h
element number str[3]=i
element number str[4]=s
element number str[5]=
element number str[6]=i
element number str[7]=s
element number str[8]=
element number str[9]=m
element number str[10]=y
element number str[11]=
element number str[12]=s
element number str[13]=t
element number str[14]=r
element number str[15]=i
element number str[16]=n
element number str[17]=g
element number str[18]=!
The string is: This is my string!
Or you can use your original scanf("%s", &str1);
#include <stdio.h>
#define N 1000
int main ()
{
int i = 0;
int k = 0;
int c;
int len;
char str[N];
char str1[N];
scanf("%s", &str1);
len = strlen(str1);
for(k = 0; k < len; k++)
{
c = str1[k];
if ( (c != EOF) && c != '\n') // EOF will work for ^D on UNIX
{
str[i] = (char) c;
printf ("element number str[%d]=%c \n", i, str[i++] );
}
else
{
str[i] = 0;
break;
}
}
printf ("The string is: %s", str);
return 0;
}
OUTPUT:
12345
element number str[1]=1
element number str[2]=2
element number str[3]=3
element number str[4]=4
element number str[5]=5
The string is: 12345

Answer 2

As stated in this answer scanf will not return until you give it a string, i.e. it skips whitespace.
As suggested in the answer and in general, using fgets is the better option.
Edit: A way to accomplish what you want would look like this:
#include <stdio.h>
#define N 1000
int main() {
int i = 0;
int j = 0;
char str[N];
do {
printf("element number str[%d] : ", i);
fgets(&str[i], 3, stdin);
i++;
} while (str[i - 1] != '\n');
printf("The string is: ");
while (i > j) {
printf("%c", str[j]);
j++;
}
return 0;
}
In the fgets you use the number 3 because pressing enter gives both a newline character [/n] and a return carriage [/r].