#include <stdio.h>

int main(void)

{

    char first_name[];

    char last_name[];

    printf("请输入您的名字: ");

    scanf("%s", last_name);

    printf("请输入您的姓氏: ");

    scanf("%s", first_name);

    printf("%s, %s", last_name, first_name);

    return ;

}

#include <stdio.h>

#include <string.h>

int main(void)

{

    char name[];

    printf("请输入您的名字: \n");

    scanf("%s", name);

    printf("\"%s\"\n", name);

    printf("\"%20s\"\n", name);

    printf("\"%-20s\"\n", name);

    printf("\"%*s\"\n", strlen(name) + , name);

    return ;

}

#include <stdio.h>

int main(void)

{

    float number;

    printf("请输入一个浮点数: \n");

    scanf("%f", &number);

    printf("The input is %.1f or %.1e\n", number, number);

    printf("The input is %+.3f or %.3e\n", number, number);

    return ;

}

#include <stdio.h>

int main(void)

{

    float feet;

    char name[];

    printf("请输入您的身高: \n");

    scanf("%f", &feet);

    printf("请输入您的名字: \n");

    scanf("%s", name);

    printf("%s, you are %.3f m tall.\n", name, feet / );

    return ;

}

#include <stdio.h>

#include <string.h>

int main(void)

{

    char lname[];

    char fname[];

    printf("请输入名字: \n");

    scanf("%s", lname);

    printf("请输入姓氏: \n");

    scanf("%s", fname);

    printf("%10s %10s\n", lname, fname);

    printf("%10d %10d\n", strlen(lname), strlen(fname));

    printf("%-10s %-10s\n", lname, fname);

    printf("%-10d %-10d\n", strlen(lname), strlen(fname));

    return ;

}

#include <stdio.h>

#include <float.h>

int main(void)

{

    double n1 = 1.0 / 3.0;

    float n2 = 1.0 / 3.0;

    printf("n1 = %.4f\n", n1);

    printf("n1 = %.12f\n", n1);

    printf("n1 = %.16f\n", n1);

    printf("n2 = %.4f\n", n2);

    printf("n2 = %.12f\n", n2);

    printf("n2 = %.16f\n", n2);

    printf("FLT_DIG = %d, DBL_DIG = %d\n", FLT_DIG, DBL_DIG);

    return ;

}

#include <stdio.h>

#define CAST1 3.785

#define CAST2 1.609

int main(void)

{

    float miles;

    float gallons;

    printf("请输入行驶的英里数: \n");

    scanf("%f", &miles);

    printf("请输入消耗汽油的加仑数: \n");

    scanf("%f", &gallons);

    printf("消耗每加仑汽油行驶的英里数: %.1f\n", miles / gallons);

    printf("每100公里的升数: %.1f\n", gallons * CAST1 / (miles * CAST2 / ));

    return ;

}