%s%d%s%d\n is a format string. It is used to specify how the information is formatted on an output. here the format string is supposed to print string followed by a digit followed by a string and then again a digit. The last symbol \n represents carriage return which marks the end of a line. In C, strings cannot be concatenated by + or , although you can combine different outputs on a single line by using the appropriate format strings (the use of format strings is to format output info.).
