1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
|
#include <stdio.h>
#include <ctype.h>
int isHexDigit(int c) {
return isdigit(c) || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F');
}
int readChar(void) {
int c = getchar();
while(c != EOF && !isHexDigit(c)) {
c = getchar();
}
return c;
}
int getDigit(char c) {
c = tolower(c);
if(c >= 'a' && c <= 'f') {
return 10 + c - 'a';
}
return c - '0';
}
int main() {
int upper = readChar();
int lower = readChar();
while(upper != EOF && lower != EOF) {
int upperDigit = getDigit(upper);
int lowerDigit = getDigit(lower);
putchar((upperDigit << 4) | lowerDigit);
upper = readChar();
lower = readChar();
}
return 0;
}
|
