c primer plus 编程练习答案第四章

最近在研读c primer plus,小白一枚，把自己做的答案写出来，望指正。

编程环境 visual studio 2010.第四章。

 1 /* Programming Exercise 4-1 */
 2 #include<stdio.h>
 3 int main(void)
 4 {
 5     char fname[40];
 6     char lname[40];
 7     printf("please enter your first name
");
 8     scanf("%s",&fname);
 9     printf("please enter your last name
");
10     scanf("%s",&lname);
11     printf("%s,%s",fname,lname);
12     return 0;
13 }

 1 /*programming exercise 4-2 */
 2 #include <stdio.h>
 3 #include<iostream>
 4 
 5 int main(void)
 6 {
 7     char first_name[40];
 8     char last_name[40];
 9     int first_name_length = 0;
10     int last_name_lenght = 0;
11     printf("What's your first name:");
12     scanf("%s", first_name);
13 
14     printf("What's your last name:");
15     scanf("%s", last_name);
16 
17     getchar();
18 
19     first_name_length = strlen(first_name);
20     last_name_lenght = strlen(last_name);
21 
22     printf("a."%s,%s"
", first_name, last_name);
23     printf("b."%20s,%20s"
", first_name, last_name);
24     printf("c."%-20s,%-20s"
", first_name, last_name);
25     printf("d.%*s,%*s
", first_name_length+3, first_name, last_name_lenght+3, last_name);
26 
27     return 0;
28 }

 1 /*programming exercise 4-3*/
 2 #include <stdio.h>
 3 int main(void)
 4 {
 5     float n;
 6     printf("enter a float number:
");
 7     scanf("%f",&n);
 8     printf("a. The input is%.1f or%.1e.
",n,n);
 9     printf("b.The input is +%.3f or %.3E.
",n,n);
10     return 0;
11 }

 1 /*programming exercise 4-4*/
 2 #include <stdio.h>
 3 #define CM_INCH 2.54
 4 int main(void)
 5 {
 6     float height_cm=0;
 7     float height_inch=0;
 8     printf("enter your height:
");
 9     scanf("%f",&height_inch);
10     getchar();
11     printf("Dabney,you are %f feet tall
",height_inch);
12     height_cm=height_inch*CM_INCH;
13     printf("Dabney,you are %f cm tall
",height_cm);
14     return 0;
15 }

 1 #include<stdio.h>
 2 int main(void)
 3 {
 4     float speed=0;
 5     float file_size=0;
 6     float download_time;
 7      printf("How much your network speed:");
 8      scanf_s("%f", &speed);
 9      printf("How much is your download file:");
10     scanf_s("%f", &file_size);
11     download_time = file_size / (speed / 8);
12     printf("At %f megabits per secnod, a file of %f magebytes
 download in %f seconds.
", speed, file_size, download_time);
13 }

 1 /*programming exercise 4-7*/
 2 #include<stdio.h>
 3 #include<float.h>
 4 int main(void)
 5 {
 6     double d_value = 1.0 / 3.0;
 7     float f_value = 1.0 / 3.0;
 8 
 9     printf("the value of FLT_DIG:%d, the value of DBL_DIG:%d
", FLT_DIG, DBL_DIG);
10     printf("the value of double:%.6lf, the value of float:%.6lf
", d_value, f_value);
11     printf("the value of double:%.12lf, the value of float:%.12lf
", d_value, f_value);
12     printf("the value of double:%.18lf, the value of float:%.18lf
", d_value, f_value);
13 
14 }

 1 /*programming exercise 4-6*/
 2 #include <stdio.h>
 3 #include<iostream>
 4 /*programming exercise 4-6*/
 5 int main(void)
 6 {
 7     char first_name[40] ;
 8     char last_name[40] ;
 9     int first_name_length = 0;
10     int last_name_length = 0;
11 
12     printf("What's your first name:");
13     scanf("%s", first_name);
14     printf("What's your last name:");
15     scanf("%s", last_name);
16     first_name_length = strlen(first_name);
17     last_name_length = strlen(last_name);
18     printf("%s %s
", first_name, last_name);
19     printf("%*d %*d
", first_name_length, first_name_length, last_name_length, last_name_length);
20     printf("%s %s
", first_name, last_name);
21     printf("%-*d %-*d
", first_name_length, first_name_length, last_name_length, last_name_length);
22 }

 1 /*programming exercise 4-8*/
 2 #include <stdio.h>
 3 #define KM_PER_MILE 1.609
 4 #define PINT_PER_GALLON 3.785
 5 int main(void)
 6 {
 7     float driven_distance = 0.0;
 8     float gas_consumption = 0.0;
 9     float pint_per_hundred_km = 0.0;
10     float mile_per_gallon = 0.0;
11     printf("How much distance have you traveled in kilometer:");
12     scanf_s("%f", &driven_distance);
13     getchar();
14 
15     printf("How much gas have you used in pint:");
16     scanf_s("%f", &gas_consumption);
17     getchar();
18 
19     pint_per_hundred_km = gas_consumption / driven_distance * 100;
20     mile_per_gallon = (driven_distance / KM_PER_MILE) / (gas_consumption / PINT_PER_GALLON);
21 
22     printf("Fuel consumptions:%f pint/100km or %f mile/gallon
", pint_per_hundred_km, mile_per_gallon);
23 }