《c primer plus》编程练习回顾-第四章

4.8 编程练习
1.

#include<stdio.h>int main(void){   char firstname[81],secondname[81];   printf("Please input your name:");   scanf("%s %s",firstname,secondname);   printf("%s %s",firstname,secondname);   return 0;}

2.

#include<stdio.h>#include<string.h>int main(void){    char name[81];    printf("Please input your name:");    scanf("%s", name);    printf("%20s\n", name);    printf("\"%-20s\"\n", name);    printf("%*s", strlen(name), name);    return 0;}

3.

#include<stdio.h>int main(void){   float a;   scanf("%f",&a);   printf("a. The input is %.1f or %.1e\n",a,a);   printf("b. The input is %+.3f or %.3E\n",a,a);   return 0;}

4.

#include<stdio.h>int main(void){    float tall;    scanf("%f", &tall);    printf("You are %.3f cm tall.\n",tall);    return 0;}

5.

#include<stdio.h>#include<string.h>int main(void){   char fname[21],sname[21];   int num1,num2;   printf("Please input your name:");   scanf("%s %s",fname,sname);   printf("%s %s\n",sname,fname);   printf("%*d %*d\n",strlen(sname),strlen(sname),strlen(fname),strlen(fname));   printf("%-*d %-*d\n",strlen(sname),strlen(sname),strlen(fname),strlen(fname));   return 0;}

6.

#include<stdio.h>#include<float.h>int main(void){   float a=1.0/3.0;   double b=1.0/3.0;   printf("%.4f,%.12f,%.16f,%d\n",a,a,a,FLT_DIG);   printf("%.4f,%.12f,%.16f,%d\n",b,b,b,DBL_DIG);}

7.

#include<stdio.h>#define GALLON 3.785 #define MILE 1.609 int main(void){float mile,gallon;printf("Please input miles and gallons:");scanf("%f %f",&mile,&gallon);printf("Miles per gallon:%.1f\n",mile/gallon);printf("Litres per 100 kilometre:%.1f\n",gallon*GALLON/(100*mile*MILE));return 0;}