在C中的同一行写入2个字符串

Question

So I want to make the hello.c program write both the first name and the last name on one line so in this form but when I run my program in this current form it gives me the error "expected â)â before string constant" I think I have the rest of the code down because I have removed that line and ran it and it works. So I just want to ask how to get 2 strings that I have already pointed to to go on the same line.

This is my code

#include <stdio.h>
int main()
{
  char firstname[20];
  char lastname[20];
  printf("What is your firstname?");
  scanf("%s", firstname);
  printf("What is your lastname?");
  scanf("%s", lastname);
  printf("Hello %s\n", firstname "%s", lastname);
  printf("Welcome to CMPUT 201!");
  }

Answer 1

You want

printf("Hello %s %s\n", firstname, lastname);

instead of

printf("Hello %s\n", firstname "%s", lastname);

Answer 2

#include<stdio.h>
#include<string.h>

int main()
{
    char first_name[20] = " ", last_name[20] = " ", full_name[40] = " ";
    printf("What is your firstname?\n");
    scanf("%s", first_name);
    printf("What is your lastname?\n");
    scanf("%s", last_name);
    sprintf(full_name,"%s %s",first_name, last_name);
    printf("name is %s\n",full_name);
    return 0;
}

I have shown the same using sprintf.

1) also in your program you are not returning anything, if dont want to return anything make it as void function. When you write int function, always make it an habbit to return the integer.

2) Also when you write the printf function always make it habit to add \\n(new line) so the output looks good

happy coding.