changing the output file name for C++

int setindex;
int caseindex;
FILE * pFile;

std::string part1 = "iccv_CV_set";
std::string part2 = "_case";
std::string part3 = "_C";
std::string part4 = "_iter";
std::string part5 = ".txt";
std::string result;


char sset[40]; // enough to hold all numbers up to 64-bits
char scase[40];
char sc[40];
char siter[40];
sprintf(sset, "%i", setindex);
sprintf(scase, "%i", caseindex);
sprintf(sc, "%i", C);
sprintf(siter, "%i", maxIter);
result = part1 + sset + part2 + scase + part3 + sc + part4 + siter + part5;

pFile = fopen(result.c_str(),"w");
fprintf(pFile,"%i\n",maxIter);
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