Create a case-insensitive string comparison function - C++ Data Type

C++ examples for Data Type:char array

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Description

Create a case-insensitive string comparison function

Demo Code

#include <iostream>
#include <cctype>
using namespace std;
int strcmp_ign_case(const char *str1, const char *str2);
void showresult(const char *str1, const char *str2, int result);
int main() {/* www  .ja  va  2s.  c  om*/
   char strA[]= "tesT";
   char strB[] = "Test";
   char strC[] = "testing";
   char strD[] = "Tea";
   int result;
   cout << "Here are the strings: " << endl;
   cout << "strA: " << strA << endl;
   cout << "strB: " << strB << endl;
   cout << "strC: " << strC << endl;
   cout << "strD: " << strD << "\n\n";
   // Compare strings ignoring case.
   result = strcmp_ign_case(strA, strB);
   showresult(strA, strB, result);
   result = strcmp_ign_case(strA, strC);
   showresult(strA, strC, result);
   result = strcmp_ign_case(strA, strD);
   showresult(strA, strD, result);
   result = strcmp_ign_case(strD, strA);
   showresult(strD, strA, result);
   return 0;
}
// A simple string comparison function that ignores case differences.
int strcmp_ign_case(const char *str1, const char *str2) {
   while(*str1 && *str2) {
      if(tolower(*str1) != tolower(*str2))
         break;
      ++str1;
      ++str2;
   }
   return tolower(*str1) - tolower(*str2);
}
void showresult(const char *str1, const char *str2, int result) {
   cout << str1 << " is ";
   if(!result)
      cout << "equal to ";
   else if(result < 0)
      cout << "less than ";
   else
      cout << "greater than ";
   cout << str2 << endl;
}

Result


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