Unable to print entire string after composing it from several partial strings - arrays

Question

My code is unable to print the Full name, its just printing out the first name. I'm a little rookie in this. This is my output:
Here's the code
#include <stdio.h>
int main ()
{
int i, j, k;
char fName[15], mName[15], lName[15], name[45];
printf ("\nEnter the First name: ");
scanf ("%s", fName);
printf ("\nEnter the Middle name: ");
scanf ("%s", mName);
printf ("\nEnter the Last name: ");
scanf ("%s", lName);
for (i = 0; i < 15; i++) {
name[i] = fName[i];
if (fName[i] == '\0') {
i++;
break;
}
}
for (j = 0; j < 15; j++) {
name[i + j] = mName[j];
if (mName[j] == '\0') {
j++;
break;
}
}
for (k = 0; k < 15; k++) {
name[i + j + k] = lName[k];
if (lName[k] == '\0') {
k++;
break;
}
}
printf ("\nFull name is %s.", name);
return 0;
}

Answer 1

Break out of the copy loop when encountering a '\0' char. In your code, the '\0' is being copied to the output, which is then being interpreted as the end of string, and in your case at the end of the first name. However, for the last name, you need to include the \0 char.
#include <stdio.h>
int main()
{
int i, j, k;
char fName[15], mName[15], lName[15], name[45];
printf("\nEnter the First name: ");
scanf("%s", fName);
printf("\nEnter the Middle name: ");
scanf("%s", mName);
printf("\nEnter the Last name: ");
scanf("%s", lName);
for (i = 0; i < 15; i++)
{
if (fName[i] == '\0')
{
i++;
break;
}
name[i] = fName[i];
}
for (j = 0; j < 15; j++)
{
if (mName[j] == '\0')
{
j++;
break;
}
name[i + j] = mName[j];
}
for (k = 0; k < 15; k++)
{
name[i + j + k] = lName[k];
if (lName[k] == '\0')
{
k++;
break;
}
}
printf("\nFull name is %s.", name);
return 0;
}

Answer 2

In your code, you copy the null terminator of each string into the name array, hence the final contents is "Alexander\0Graham\0Bell". printf stops at the first null byte it finds in the string argument for %s so only the first name is output.
You should instead use a separate index for the source and destination arrays and set a space between the 3 parts of the name.
Note also that you should tell scanf() to stop reading after 14 bytes to avoid storing characters beyond the end of the arrays on overlong user input and test the return value to detect invalid input.
Here is a modified version:
#include <stdio.h>
int main() {
char fName[15], mName[15], lName[15], name[45];
int i, j;
printf("\nEnter the First name: ");
if (scanf("%14s", fName) != 1)
return 1;
printf("\nEnter the Middle name: ");
if (scanf("%14s", mName) != 1)
return 1;
printf("\nEnter the Last name: ");
if (scanf("%14s", lName) != 1)
return 1;
i = 0;
for (j = 0; fName[j] != '\0'; j++) {
name[i++] = fName[j];
}
name[i++] = ' ';
for (j = 0; mName[j] != '\0'; j++) {
name[i++] = mName[j];
}
name[i++] = ' ';
for (j = 0; lName[j] != '\0'; j++) {
name[i++] = lName[j];
}
name[i] = '\0';
printf("\nFull name is %s.", name);
return 0;
}
There is a simpler solution using string functions:
#include <stdio.h>
#include <string.h>
int main() {
char fName[15], mName[15], lName[15], name[45];
printf("\nEnter the First name: ");
if (scanf("%14s", fName) != 1)
return 1;
printf("\nEnter the Middle name: ");
if (scanf("%14s", mName) != 1)
return 1;
printf("\nEnter the Last name: ");
if (scanf("%14s", lName) != 1)
return 1;
strcpy(name, fName);
strcat(name, " ");
strcat(name, mName);
strcat(name, " ");
strcat(name, lName);
printf("\nFull name is %s.", name);
return 0;
}
And even simpler using just snprintf:
#include <stdio.h>
int main() {
char fName[15], mName[15], lName[15], name[45];
printf("\nEnter the First name: ");
if (scanf("%14s", fName) != 1)
return 1;
printf("\nEnter the Middle name: ");
if (scanf("%14s", mName) != 1)
return 1;
printf("\nEnter the Last name: ");
if (scanf("%14s", lName) != 1)
return 1;
snprintf(name, sizeof name, "%s %s %s", fName, mName, lName);
printf("\nFull name is %s.", name);
return 0;
}

Answer 3

Others have explained why your program didn't print the full name. Phillip Ngan suggested a correction, but it pastes the individual names together without spacing. To get the full name in the usual form, you just need to replace the line i++; in your code with
name[i++] = ' ';
and the line j++ with
name[i+j++] = ' ';
Of course, you could replace all the for loops with just
sprintf(name, "%s %s %s", fName, mName, lName);
And also of course you should note David C. Rankin's comment.