if (n>7) printf(\ if (n>8) printf(\ if (n>9) printf(\ printf(\ } }

return 0; }

5-9-2

#include <> int main() {int m,s,i;

for (m=2;m<1000;m++) {s=0;

for (i=1;i

if ((m%i)==0) s=s+i; if(s==m)

{printf(\ for (i=1;i

#include <> int main() {

int i,n=20;

double a=2,b=1,s=0,t; for (i=1;i<=n;i++) {

s=s+a/b; t=a, a=a+b, b=t; }

printf(\ return 0; }

5-11

#include <> int main() {

double sn=100,hn=sn/2; int n;

for (n=2;n<=10;n++) {

sn=sn+2*hn; /*第n次落地时共经过的米数*/ hn=hn/2; /*第n次反跳高度*/ }

printf(\第10次落地时共经过%f米\\n\ printf(\第10次反弹%f米\\n\ return 0; } 5-12

#include <> int main() {

int day,x1,x2; day=9; x2=1;

while(day>0)

{x1=(x2+1)*2; /*第1天的桃子数是第2天桃子数加1后的2倍.*/ x2=x1; day--; }

printf(\ return 0; } 5-13

#include <> #include <> int main() {

float a,x0,x1;

printf(\ scanf(\ x0=a/2;

x1=(x0+a/x0)/2; do

{x0=x1;

x1=(x0+a/x0)/2;

}while(fabs(x0-x1)>=1e-5);

printf(\ is %\\n\ return 0; } 5-14

#include <> #include <> int main()

{double x1,x0,f,f1; x1=; do

{x0=x1;

f=((2*x0-4)*x0+3)*x0-6; f1=(6*x0-8)*x0+3; x1=x0-f/f1;

}while(fabs(x1-x0)>=1e-5);

printf(\ return 0; } 5-15

#include <> #include <> int main()

{float x0,x1,x2,fx0,fx1,fx2; do

{printf(\ scanf(\ fx1=x1*((2*x1-4)*x1+3)-6; fx2=x2*((2*x2-4)*x2+3)-6; }while(fx1*fx2>0); do

{x0=(x1+x2)/2;

fx0=x0*((2*x0-4)*x0+3)-6; if ((fx0*fx1)<0) {x2=x0; fx2=fx0; }

else {x1=x0; fx1=fx0; }

}while(fabs (fx0)>=1e-5); printf(\ return 0; } 5-16

#include <> int main() {int i,j,k;

for (i=0;i<=3;i++) {for (j=0;j<=2-i;j++) printf(\

for (k=0;k<=2*i;k++) printf(\ printf(\ }

for (i=0;i<=2;i++) {for (j=0;j<=i;j++) printf(\

for (k=0;k<=4-2*i;k++) printf(\ printf(\ }

return 0; } 5-17

#include <> int main() {

char i,j,k; /*是a的对手;j是b的对手;k是c的对手*/ for (i='x';i<='z';i++) for (j='x';j<='z';j++) if (i!=j)

for (k='x';k<='z';k++) if (i!=k && j!=k) if (i!='x' && k!='x' && k!='z') printf(\ return 0;