N. Aharon N. Aharon - 28 days ago 7
C Question

how to compare words on C

i tried to make a code for a friend in C but i have no idea why it's not working, could someone please help me? (i want a simple version-fix if it's possible, because i've only started to study c a couple of weeks ago)

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


int main ()

{

char *name="alina";
char *input;
printf ("what's your name? \n");
scanf ("%s",&input);
if (input=="alina")
printf("your name is %s good job!\n ",&name);
if (input!="alina")
printf("are you sure? open the program again and insert the correct name");
while (1);

Answer

You did some errors. First, if you want to insert a string, you can use the %s, but you have to use an array of char in which you can store that string. That's, you have to write something like this.

char input[100];
scanf("%s", input);

and then it'll work. This snippet of code means: I need to insert (store) a string. So first I create a place in which I can store it (pay attention that the string must be maximum of 99 characters; my array has size 100, but the last character is used to represent the end of the string), and then I use the scanf to write what I want.

The second error is that if you want to compare two strings, you can't simply use the == or !=, like when you do with numbers. The string.h library lets you use the strcmp function, like this:

if (strcmp(name, input) == 0)   // this means the strings are equal
   ...
else
   ...

remembering that

char* name = "Alina";
char input[100];

Eventually, here you're an inspected version of your code:

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

int main() {

    char* name = "Alina";
    char input[100];
    printf("What's your name?\n");
    scanf("%s", input);
    if (strcmp(name, input) == 0)
        printf("Your name is %s good job!\n", name);
    else
        printf("Are you sure? Open the program again and insert the correct name\n");

    return 0;
}

The while(1) at the end of your code is absolutely dangerous, because it starts an infinite loop that never ends, crashing your program. You want to definitely remove it!