C 字符串和格式化输入与输出

#include<stdio.h>
#include<string.h>        //1提供strlen（）的函数原型
#define DENSITY   62.4    //2预处理命令
int main(void)
{
    float weight,volume;
    int size,letters;
    char name[40];    //3定义一个长度为40的数组

    printf("Hi! What‘s your first name?\n");
    scanf("%s",name);
    printf("%s,What‘s your weight in pounds?\n",name);
    scanf("%f",&weight);
    size=sizeof  name;   //4  数组name[]的长度
    letters=strlen(name);//5  调用函数strlen()
    volume=weight/DENSITY;
    printf("well,%s,your volume is %2.2f  cubic feet.\n",name,volume);//%2.2f表示字符宽度为2，精确到小数点后两位
    printf("Also,your first name has %d letters,\n",letters);
    printf("and we have %d bytes to store it in.\n",size);
    return 0;
}

sizeof（）和strlen（） 
#include<stdio.h>
#include<string.h>
#define PRAISE  "What a super marvelous name!"
int main(void)
{
    char name[40];
    printf("What‘s your name?\n");
    scanf("%s",name);
    printf("Hello,%s.%s\n",name,PRAISE);
    printf("Your name of %d letrers occupies %d memory cells.\n",
        strlen(name),sizeof(name));//sizeof name
    printf("The phrase of praise has %d letters",
        strlen(PRAISE));
    printf("and occupies %d memory cells.\n",sizeof(PRAISE));//sizeof PRAISE
    return 0;
}

printf()打印较长字符串
#include<stdio.h>
int main(void)
{
    printf("Here‘s one way to print a ");
    printf("long string.\n");//a
    printf("Here‘s another way to print a \
long string.\n");//b
    printf("Here‘s the newest way to print a "
        "long string.\n");//c
    return 0;
}