How to compare two characters without case sensitivity in C?

Question

I am trying to compare two specific characters in two strings,but I want to make the comparing without case sensitivity. How can I do this?

right now I am using a code like that:

if (str1[i]==str2[j]) printf("Equal");

but I want to do this without case sensivity.

Thank you in advance for taking your time to help!

What are the language, character encoding / code page and the type of the element of your strings? — Alexey Frunze, Mar 18 '19 at 07:38

Alex · Accepted Answer · 2019-03-17T14:38:13.843

6

You can use low case for both chars, for example by using tolower function:

if (tolower(str1[i])==tolower(str2[j])) printf("Equal");

Also keep in mind: tolower does not work for multibyte char. So for those chars you should use other function

edited Mar 17 '19 at 14:38

answered Mar 17 '19 at 14:29

Alex

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will tolower() function effect the original char in string? either way thank you for your answer! – Anthony Mar 17 '19 at 14:31
no, you pass char by value, not by pointer. so its impossible for this function to change it – Alex Mar 17 '19 at 14:32
Thank you for your help! – Anthony Mar 17 '19 at 14:34

BEPP · Answer 2 · 2019-03-18T06:39:41.777

1

We can achieve your requirement by converting both of the character to either upper or lower case character using toupper() or tolower().

Example:

#include <stdio.h>
#include <ctype.h> //For tolower()

int main()
{
    char str1[]="Time", str2[]="time";
    /*
     * Just for an example i am comparing the first char
     * from 2 different strings.
     */
    if(tolower(str1[0]) ==tolower(str2[0])) {
        printf("Char's are equal\n");
    }
    else {
        printf("Char's are not equal");
    }
    return 0;
}

Output:

Char's are equal

edited Mar 18 '19 at 06:39

answered Mar 17 '19 at 14:38

BEPP

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1
12
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You have two strings, but you only compare their first char. Shouldn't there be a loop? – Paul Ogilvie Mar 17 '19 at 15:20

How to compare two characters without case sensitivity in C?

2 Answers2