例:一个简单的宏定义 #define e 2.71427 # include“math.h” ma in float sum sum=sqrt(E)+E+E*E+E*E*E十E*E米; printf(“%f”,sum); 若要把E的值改为2.71427例: 一个简单的宏定义 #define E 2.71828 #include “math.h” main() { float sum; sum=sqrt(E)+E+E*E+E*E*E+E*E*E*E; printf(“%f”,sum); } 若要把E的值改为2.71427 2.71427