练习 6：变量类型

include <stdio.h>

int main(int argc, char *argv[])
{
    int distance = 100;
    float power = 2.345f;
    double super_power = 56789.4532;
    char initial = 'A';
    char first_name[] = "Zed";
    char last_name[] = "Shaw";

    printf("You are %d miles away.\n", distance);
    printf("You have %f levels of power.\n", power);
    printf("You have %f awesome super powers.\n", super_power);
    printf("I have an initial %c.\n", initial);
    printf("I have a first name %s.\n", first_name);
    printf("I have a last name %s.\n", last_name);
    printf("My whole name is %s %c. %s.\n",
            first_name, initial, last_name);

    return 0;
}

附加题 1

寻找其他通过修改printf使这段C代码崩溃的方法。

#include <stdio.h>

int main(int argc, char *argv[])
{
    int distance = 100;
    float power = 2.345f;
    double super_power = 56789.4532;
    char initial = 'A';
    char first_name[] = "Zed";
    char last_name[] = "Shaw";

    // Incorrect format specifiers:
    printf("You are %f miles away.\n", distance); // should be %d
    printf("You have %d levels of power.\n", power); // should be %f
    printf("You have %s awesome super powers.\n", super_power); // should be %f
    printf("I have an initial %s.\n", initial); // should be %c
    printf("I have a first name %d.\n", first_name); // should be %s
    printf("I have a last name %f.\n", last_name); // should be %s
    printf("My whole name is %s %d. %c.\n",
            first_name, initial, last_name); // %d and %c should be swapped

    return 0;
}

附加题 2

搜索“printf格式化”，试着使用一些高级的占位符。

看看练习 3 呢。

附加题 3

研究可以用几种方法打印数字。尝试以八进制或十六进制打印，或者其它你找到的方法。

#include <stdio.h>

int main() {
    int number = 255;
    float power = 123.456f;

    // 打印整数
    printf("Decimal: %d\n", number);
    printf("Octal: %o\n", number);
    printf("Hexadecimal (lowercase): %x\n", number);
    printf("Hexadecimal (uppercase): %X\n", number);
    printf("Unsigned Decimal: %u\n", number);

    // 打印浮点数
    printf("Default format: %f\n", power);
    printf("Scientific notation: %e\n", power);
    printf("Shortest representation: %g\n", power);

    // 打印带有精度控制的浮点数
    printf("Two decimal places: %.2f\n", power);
    printf("Four decimal places: %.4f\n", power);
    printf("Scientific notation with two significant figures: %.2e\n", power);
    printf("Shortest representation with four significant figures: %.4g\n", power);

    return 0;
}

附加题 4

试着打印空字符串，即""。

#include <stdio.h>

int main() {
    // 打印空字符串
    printf("This is an empty string: \"%s\"\n", "");

    // 打印空字符串在其他字符串的上下文中
    char empty_string[] = "";
    printf("Here is another empty string: \"%s\"\n", empty_string);

    return 0;
}