例 #include <stdio. h / File-Name: F9-5-1C*/ #include"c. Itcluser f9-5-1c float absolute(float x #include"c \tcluser f9-5-2c i if(x=0)return(x) main / File-Name: F9-5-2C*/ else return(-x); i floa #include <math h> prIn float real sqrt(float x) :) sca i float x1=1.0, x2 a x2=0.5*(x1+x/x1) X while(fabs(x2-XI>lE-5) prI {X1=x2 x, real sart(y)) egx2=0.5*(x1+xx1) prI real sqrt(y)) return(X2)例：求任意一个实数的平方根。 #include <stdio.h> #include "c:\tc\user\f9-5-1.c" #include "c:\tc\user\f9-5-2.c" main() { float x,y; printf("Please input a real number: "); scanf("%f",&x); y=absolute(x); if(x<0) printf("SQRT(%.2f) is: %.4f i",x,real_sqrt(y)); else printf("SQRT(%.2f) is: %.4f",x,real_sqrt(y)); } /* File-Name: F9-5-1.C */ float absolute(float x) { if(x>=0) return (x); else return (-x); } /* File-Name: F9-5-2.C */ #include <math.h> float real_sqrt(float x) { float x1=1.0,x2; x2=0.5*(x1+x/x1); while(fabs(x2-x1)>1E-5) { x1=x2; x2=0.5*(x1+x/x1); } return (x2); }