数字转化为标准string(opencv)

format 函数

Returns a text string formatted using the printf-like expression.

string format( const char* fmt, ... )

Parameters
fmt – printf -compatible formatting specifiers.

The function acts like sprintf but forms and returns an STL string. It can be used to form an error message in the

Exception() constructor.

举例： 欲创建一个文件是 ABC0004.txt。

int No = 4;

filename = "ABC" + cv::format("%.4d",No) + ".txt";