考虑到你正在学习CS50，一个很好的书签页面是https://manual.cs50.io/，它包含了你在任何类Unix操作系统（例如https://man.openbsd.org/）上都能找到的手册的简化版本。
扫描此页面，在string.h下，您将看到：

• strcmp-比较两个字符串

strcmp页面解释了该函数的 prototype 为

int strcmp(string s1, string s2);

字符串
它会返回
0如果s1与s2相同
在使用中，这看起来像

if (0 == strcmp("Matchbox", select))
{
    puts("That will be 50 buckaroonies!");
}
else if (0 == strcmp("Wool Hat", select))
{
    puts("That will be 125 buckaroonies!");
}

型
在实践中，你可能希望以某种方式 * 循环 * 这些选项，而不是手工编写每个比较。考虑下面的例子，使用两个等长的 * 数组 * 表示商店中的物品及其价格：

#include <cs50.h>
#include <stdio.h>
#include <string.h>

int string_to_price(string item)
{
    string items[] = { "Matchbox", "Wool Hat", "Heavy Coat", "Canned Food" };
    int prices[] = { 50, 125, 250, 25 };

    for (size_t i = 0; i < (sizeof items / sizeof *items); i++)
    {
        if (0 == strcmp(items[i], item))
        {
            return prices[i];
        }
    }

    /* item does not exist */
    return -1;
}

int main(void)
{
    int buckaroonies = 500;
    printf("Hey chum, welcome to the item shop. You've got a handful 'o coin on ya, huh?\nYou came to the right place, we got the best wares in town!\n\n");
    printf("Store:\n\nMatchbox - 50\nWool Hat - 125\nHeavy Coat - 250\nCanned Food - 25\n");
    string select = get_string ("What'll it be? You have %i buckaroonies, pal.\n", buckaroonies);

    int price = string_to_price(select);

    if (-1 == price)
    {
        puts("We aint got that, pal.");
    }
    else
    {
        printf("That %s will cost ya %i buckaroonies!\n", select, price);
    }
}

Hey chum, welcome to the item shop. You've got a handful 'o coin on ya, huh?
You came to the right place, we got the best wares in town!

Store:

Matchbox - 50
Wool Hat - 125
Heavy Coat - 250
Canned Food - 25
What'll it be? You have 500 buckaroonies, pal.
Canned Food
That Canned Food will cost ya 25 buckaroonies!

的字符串
稍后，当您更习惯时，用一个structures数组替换这两个数组会更健壮。
标签：How do I determine the size of my array in C?