How do you get mismatch count between two string c language?

Answer 1

The simplest answer is to XOR (eXclusive OR) each corresponding character. If the result is non-zero, you have a mismatch so you increment the count. Note that you must always loop through the shorter of the two strings. The difference in length is also a mismatch.

The following function shows the basic principal:

unsigned mismatch_count (const char* str1, const char* str2) {

/* some variables */

unsigned len, len1, len2, index, count;

/* determine length of each string */

len1=strlen (str1);

len2=strlen (str2);

/* store the shortest length */

len=len1<len2?len1:len2;

/* if the strings are different lengths, the difference is a mismatch */

count=(len==len1)?len2-len1:len1-len2;

/* XOR each corresponding character, incrementing the count when non-zero */

for (index=0; index<len; ++index) {

if ((str1[index]^str2[index])!=0) {

++count;

}

}

return count;

}