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如何用更少的代码重构它？ 这是家庭作业，使用频率分布破解凯撒密文。
我已经完成了作业，但希望它更干净。
int main(int argc, char **argv){
// first allocate some space for our input text (we will read from stdin).
char* text = (char*)malloc(sizeof(char)*TEXT_SIZE+1);
char textfreq[ALEN][2];
char map[ALEN][2];
char newtext[TEXT_SIZE];
char ch, opt, tmpc, tmpc2;
int i, j, tmpi;
// Check the CLI arguments and extract the mode: interactive or dump and store in opt.
if(!(argc == 2 && isalpha(opt = argv[1][1]) && (opt == 'i' || opt == 'd'))){
printf("format is: '%s' [-d|-i]\n", argv[0]);
exit(1);
}
// Now read TEXT_SIZE or feof worth of characters (whichever is smaller) and convert to uppercase as we do it.
for(i = 0, ch = fgetc(stdin); i < TEXT_SIZE && !feof(stdin); i++, ch = fgetc(stdin)){
text[i] = (isalpha(ch)?upcase(ch):ch);
}
text[i] = '\0'; // terminate the string properly.
// Assign alphabet to one dimension of text frequency array and a counter to the other dimension
for (i = 0; i < ALEN; i++) {
textfreq[i][0] = ALPHABET[i];
textfreq[i][1] = 0;
}
// Count frequency of characters in the given text
for (i = 0; i < strlen(text); i++) {
for (j = 0; j < ALEN; j++) {
if (text[i] == textfreq[j][0]) textfreq[j][1]+=1;
}
}
//Sort the character frequency array in descending order
for (i = 0; i < ALEN-1; i++) {
for (j= 0; j < ALEN-i-1; j++) {
if (textfreq[j][1] < textfreq[j+1][1]) {
tmpi = textfreq[j][1];
tmpc = textfreq[j][0];
textfreq[j][1] = textfreq[j+1][1];
textfreq[j][0] = textfreq[j+1][0];
textfreq[j+1][1] = tmpi;
textfreq[j+1][0] = tmpc;
}
}
}
//Map characters to most occurring English characters
for (i = 0; i < ALEN; i++) {
map[i][0] = CHFREQ[i];
map[i][1] = textfreq[i][0];
}
// Sort the map lexicographically
for (i = 0; i < ALEN-1; i++) {
for (j= 0; j < ALEN-i-1; j++) {
if (map[j][0] > map[j+1][0]) {
tmpc = map[j][0];
tmpc2 = map[j][1];
map[j][0] = map[j+1][0];
map[j][1] = map[j+1][1];
map[j+1][0] = tmpc;
map[j+1][1] = tmpc2;
}
}
}
if(opt == 'd'){
decode_text(text, newtext, map);
} else {
// do option -i
}
// Print alphabet and map to stderr and the decoded text to stdout
fprintf(stderr, "\n%s\n", ALPHABET);
for (i = 0; i < ALEN; i++) {
fprintf(stderr, "%c", map[i][1]);
}
printf("\n%s\n", newtext);
return 0;
}