The shortest C program to calculate the multiplication of large numbers

#include <stdio.h>char s[99],t[99];int m,n;void r (int i,int c) {  int j=0,k=i;  while (k) c+=s[j++]*t[k---1];  if (i) r (I-1,C/10);  printf ("%d", c%10);} void Main () {  gets (s), gets (t);  while (S[n]) s[n++]-=48;  while (T[m]) t[m++]-=48;  R (m+n-1,0);}



Description
1. This program receives 2 integer input from the keyboard, calculates their product, and outputs the result.
The total length of the two integers entered cannot be greater than 99.
2. This program is no big deal, just for fun.
3. The main goal of this program is to use the shortest possible code to achieve large number multiplication. The above code
Can be compiled and run under VC. Compile under GCC to omit the # include statement and the Void keyword,
Remove carriage returns and unnecessary spaces, with a total length of only 196 bytes.
In addition, the program deliberately avoids using arrays to store intermediate and final results.
To do this, recursive procedures are used, and the use of recursion simplifies the code.
4. In the actual work, do not write such procedures, otherwise you will be scolded to death.
5. Do not use this procedure to test your students and interviewers, even if he claims to be proficient in C language.

The characteristics of such a shortest program
1. Global variables are often used, and the advantage of global variables is that
1). Automatic initialization of arrays and a single variable of 0 saves some variable initialization statements.
2). Initializing the array to 0 also makes the logic simpler, eliminating the judgment of certain boundary values.
3). In subroutines, you can omit certain parameter definitions and parameter passing statements by using global variables directly.

2. In expressions, a large number of operators, such as "+ +" or "--", are often used to
With stone effect, can shorten the code length effectively. But at work, I strongly oppose the use of
This type of operator.

3. In comparison statements, it is very rare to use statements such as if (I>=C), but instead use the "if (i)"
notation, which is 3 fewer letters than ">=c".

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The shortest C program to calculate the multiplication of large numbers