A typical example: the old days

#include <stdio.h>

#include <stdlib.h>

#include <ctype.h>

#include <string.h>

#define ishex(x) (((x) >= '0' && (x) <= '9') || ((x) >= 'a' && (x) <= 'f') || \

((x) >= 'A' && (x) <= 'F'))

int htoi(char *s) {

int value;

char c;

c = s[0];

if(isupper(c)) c = tolower(c);

value=(c >= '0' && c <= '9' ? c - '0' : c - 'a' + 10) * 16;

c = s[1];

if(isupper(c)) c = tolower(c);

value += c >= '0' && c <= '9' ? c - '0' : c - 'a' + 10;

return(value);

}

void main(int argc, char *argv[]) {

char params, data, dest, s, *tmp;

char name, age;

puts("Content-type: text/html\r\n");

puts("<html><header><title>Form Example</title></header>");

puts("<body><h1>My Example Form</h1>");

puts("<form action=\"form.cgi\" method=\"POST\">");

puts("Name: <input type=\"text\" name=\"name\">");

puts("Age: <input type=\"text\" name=\"age\">");

puts("</form>");

data = getenv("QUERY_STRING");

if(data) {

params = data; dest = data;

while(*data) {

if(data=='+') dest=' ';

else if(data == '%' && ishex((data+1)) && ishex(*(data+2))) {

*dest = (char) htoi(data + 1);

data+=2;

} else dest = data;

data++;

dest++;

}

*dest = '\0';

s = strtok(params,"&");

do {

tmp = strchr(s,'=');

if(tmp) {

*tmp = '\0';

if(!strcmp(s,"name")) name = tmp+1;

else if(!strcmp(s,"age")) age = tmp+1;

}

} while(s=strtok(NULL,"&"));

printf("Hi %s, you are %s years old\n",name,age);

}

puts("</body></html>");

}

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A typical example: the old days

#include <stdio.h>

#include <stdlib.h>

#include <ctype.h>

#include <string.h>

#define ishex(x) (((x) >= '0' && (x) <= '9') || ((x) >= 'a' && (x) <= 'f') || \

((x) >= 'A' && (x) <= 'F'))

int htoi(char *s) {

int value;

char c;

c = s[0];

if(isupper(c)) c = tolower(c);

value=(c >= '0' && c <= '9' ? c - '0' : c - 'a' + 10) * 16;

c = s[1];

if(isupper(c)) c = tolower(c);

value += c >= '0' && c <= '9' ? c - '0' : c - 'a' + 10;

return(value);

}

void main(int argc, char *argv[]) {

char *params, *data, *dest, *s, *tmp;

char *name, *age;

puts("Content-type: text/html\r\n");

puts("<html><header><title>Form Example</title></header>");

puts("<body><h1>My Example Form</h1>");

puts("<form action=\"form.cgi\" method=\"POST\">");

puts("Name: <input type=\"text\" name=\"name\">");

puts("Age: <input type=\"text\" name=\"age\">");

puts("</form>");

data = getenv("QUERY_STRING");

if(data) {

params = data; dest = data;

while(*data) {

if(*data=='+') *dest=' ';

else if(*data == '%' && ishex(*(data+1)) && ishex(*(data+2))) {

*dest = (char) htoi(data + 1);

data+=2;

} else *dest = *data;

data++;

dest++;

}

*dest = '\0';

s = strtok(params,"&");

do {

tmp = strchr(s,'=');

if(tmp) {

*tmp = '\0';

if(!strcmp(s,"name")) name = tmp+1;

else if(!strcmp(s,"age")) age = tmp+1;

}

} while(s=strtok(NULL,"&"));

printf("Hi %s, you are %s years old\n",name,age);

}

puts("</body></html>");

}

char params, data, dest, s, *tmp;

char name, age;

if(data=='+') dest=' ';

else if(data == '%' && ishex((data+1)) && ishex(*(data+2))) {

} else dest = data;