C语言 C 中的字符比较
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Char Comparison in C
提问by dclark
I'm trying to compare two chars to see if one is greater than the other. To see if they were equal, I used strcmp. Is there anything similar to strcmpthat I can use?
我正在尝试比较两个字符以查看一个字符是否大于另一个字符。为了查看它们是否相等，我使用了strcmp. 有什么类似于strcmp我可以使用的东西吗？
回答by Victor
A charvariable is actually an 8-bit integral value. It will have values from 0to 255. These are ASCII codes. 0stands for the C-null character, and 255stands for an empty symbol.
甲char变量实际上是8位的整数值。它将具有从0到 的值255。这些是ASCII 码。0代表 C-null 字符，255代表空符号。
So, when you write the following assignment:
因此，当您编写以下作业时：
char a = 'a';
It is the same thing as:
它与以下内容相同：
char a = 97;
So, you can compare two charvariables using the >, <, ==, <=, >=operators:
因此，您可以char使用>, <, ==, <=,>=运算符比较两个变量：
char a = 'a';
char b = 'b';
if( a < b ) printf("%c is smaller than %c", a, b);
if( a > b ) printf("%c is smaller than %c", a, b);
if( a == b ) printf("%c is equal to %c", a, b);
回答by Vorsprung
In C the char type has a numeric value so the > operator will work just fine for example
在 C 中，char 类型有一个数值，因此 > 运算符将正常工作，例如
#include <stdio.h>
main() {
char a='z';
char b='h';
if ( a > b ) {
printf("%c greater than %c\n",a,b);
}
}
回答by Ayman Khamouma
I believe you are trying to compare two strings representing values, the function you are looking for is:
我相信您正在尝试比较表示值的两个字符串，您正在寻找的函数是：
int atoi(const char *nptr);
or
或者
long int strtol(const char *nptr, char **endptr, int base);
these functions will allow you to convert a string to an int/long int:
这些函数将允许您将字符串转换为 int/long int：
int val = strtol("555", NULL, 10);
and compare it to another value.
并将其与另一个值进行比较。
int main (int argc, char *argv[])
{
long int val = 0;
if (argc < 2)
{
fprintf(stderr, "Usage: %s number\n", argv[0]);
exit(EXIT_FAILURE);
}
val = strtol(argv[1], NULL, 10);
printf("%d is %s than 555\n", val, val > 555 ? "bigger" : "smaller");
return 0;
}
