C++ source code to count strings of UTF-8.

CntStrUtf8.cpp

#include <iostream>
#include <string.h>

using namespace std;

/*
 * [CLASS] Proc
 */
class Proc
{
    int cntByte(unsigned char);  // Count bytes

public:
    int cntStr(const char*);     // Count stings
};

/*
 * Count strings
 */
int Proc::cntStr(const char *cStr)
{
   int i = 0, iCnt = 0;

   while (cStr[i] != '\0') {
       iCnt++;
       i += cntByte(cStr[i]);
   }

   return iCnt;
}

/*
 * Count bytes
 */
int Proc::cntByte(unsigned char cChar)
{
   int iByte;

   if ((cChar >= 0x00) && (cChar <= 0x7f)) {
       iByte = 1;
   } else if ((cChar >= 0xc2) && (cChar <= 0xdf)) {
       iByte = 2;
   } else if ((cChar >= 0xe0) && (cChar <= 0xef)) {
       iByte = 3;
   } else if ((cChar >= 0xf0) && (cChar <= 0xf7)) {
       iByte = 4;
   } else if ((cChar >= 0xf8) && (cChar <= 0xfb)) {
       iByte = 5;
   } else if ((cChar >= 0xfc) && (cChar <= 0xfd)) {
       iByte = 6;
   } else {
       iByte = 0;
   }

   return iByte;
}

/*
 * Execution
 */
int main(){
    const char* cStr = "これは文字数 Count の ﾃｽﾄ です。";
    int iCnt;

    try {
        Proc objMain;
        iCnt = objMain.cntStr(cStr);
        cout << "* " << cStr << "\n"
             << "  => " << strlen(cStr) << " Bytes, "
             << iCnt << " Strings" << endl;
    } catch (const char* e) {
        cerr << "[EXCEPTION] " << e << endl;
        return 1;
    }
    return 0;
}