C++读取float型数据，小数部分出错，请教！

ifstream infile("C://temp/AdaptiveWeight/AdaptiveWeight/keypoints.txt"); ofstream outfile("C://temp/AdaptiveWeight/AdaptiveWeight/duqushujutest.txt"); if(!infile) { cout<<"Unable to open the file !"; exit(1); } if(!outfile) { cout<<"Unable to open the file !"; exit(1); } int i=0; float Keyp[3][Dpoint]={0}; while(i<Dpoint) { infile>>Keyp[0][i]; infile>>Keyp[1][i]; infile>>Keyp[2][i]; i++; }