How to compare strings in an "if" statement?

Question

I want to test and see if a variable of type "char" can compare with a regular string like "cheese" for a comparison like:

#include <stdio.h>

int main()
{
    char favoriteDairyProduct[30];

    scanf("%s",favoriteDairyProduct);

    if(favoriteDairyProduct == "cheese")
    {
        printf("You like cheese too!");
    }
    else
    {
        printf("I like cheese more.");
    }

    return 0;
}

(What I actually want to do is much longer than this but this is the main part I'm stuck on.) So how would one compare two strings in C?

By the way, using scanf() like that is a very serious bug. If you enter a word longer than 30 characters, your program will probably crash. fgets() is safer. — Jason Orendorff, Sep 27 '12 at 11:55

score 36 · Accepted Answer · edited Mar 07 '13 at 10:12

36

You're looking for the function strcmp, or strncmp from string.h.

Since strings are just arrays, you need to compare each character, so this function will do that for you:

if (strcmp(favoriteDairyProduct, "cheese") == 0)
{
    printf("You like cheese too!");
}
else
{
    printf("I like cheese more.");
}

Further reading: strcmp at cplusplus.com

edited Mar 07 '13 at 10:12

Adriano Repetti

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answered Nov 22 '11 at 05:43

Kaslai

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score 5 · Answer 2 · answered Nov 22 '11 at 05:44

5

if(strcmp(aString, bString) == 0){
    //strings are the same
}

godspeed

answered Nov 22 '11 at 05:44

Trevor Arjeski

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score 4 · Answer 3 · edited Mar 30 '17 at 21:26

4

if(!strcmp(favoriteDairyProduct, "cheese"))
{
    printf("You like cheese too!");
}
else
{
    printf("I like cheese more.");
}

edited Mar 30 '17 at 21:26

HDJEMAI

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answered Mar 30 '17 at 18:26

SANTHOSH.SJ

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3

What is different here than the accepted answer? – zar Mar 30 '17 at 18:32
1

@zar Simple difference, but difference the negation instead of ==0. – quantummind Mar 30 '17 at 19:29

score 4 · Answer 4 · edited Jun 02 '17 at 19:48

4

Have a look at the functions strcmp and strncmp.

edited Jun 02 '17 at 19:48

Peter Mortensen

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answered Nov 22 '11 at 05:42

Adrian Cornish

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score 3 · Answer 5 · edited Nov 22 '11 at 14:09

3

You can't compare array of characters using == operator. You have to use string compare functions. Take a look at Strings (c-faq).

The standard library's strcmp function compares two strings, and returns 0 if they are identical, or a negative number if the first string is alphabetically "less than" the second string, or a positive number if the first string is "greater."

edited Nov 22 '11 at 14:09

Mike Samuel

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answered Nov 22 '11 at 05:42

KV Prajapati

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How to compare strings in an "if" statement?

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