commit 1715254ba00f33007f0e55c46b6e82bb30a907f9
parent 6098c3f26b27f313ff82a1e08ea6e18056f64c33
Author: Andrew Laack <andrew@laack.co>
Date: Sun, 26 Oct 2025 21:11:48 -0500
Completed most of chapter 1
Diffstat:
5 files changed, 248 insertions(+), 0 deletions(-)
diff --git a/c-book/ch1/count-digits.c b/c-book/ch1/count-digits.c
@@ -0,0 +1,32 @@
+#include <stdio.h>
+
+int main(){
+ int c, i, nwhite, nother;
+
+ int ndigit[10];
+
+ nwhite = nother = 0;
+
+ for (i = 0 ; i < 10; ++i){
+ ndigit[i] = 0;
+ }
+
+ while((c = getchar()) != EOF){
+ if(c >= '0' & c <= '9'){
+ ++ndigit[c-'0'];
+ }
+ else if(c == ' ' || c == '\n' || c == '\t'){
+ ++nwhite;
+ }
+ else{
+ ++nother;
+ }
+ }
+ printf("digits = ");
+ for(i = 0; i < 10; ++i){
+ printf(" %d", ndigit[i]);
+ }
+ printf(", white space = %d, other = %d\n", nwhite, nother);
+
+ return 0;
+}
diff --git a/c-book/ch1/count-digitsv2.c b/c-book/ch1/count-digitsv2.c
@@ -0,0 +1,32 @@
+#include <stdio.h>
+
+int main(){
+
+
+ int digits [10];
+ int countWhite, countOther;
+ char current;
+
+ for(int i = 0; i < 10; ++i)
+ digits[i] = 0;
+
+ while((current = getchar()) != EOF)
+ if (current >= '0' && current <= '9')
+ digits[current - '0'] += 1;
+ else if(current == '\t' || current == '\n' || current == ' ')
+ countWhite += 1;
+ else
+ countOther += 1;
+
+
+ printf("\nDigits: ");
+
+ for(int i = 0; i < 10; ++i)
+ printf("%d ", digits[i]);
+
+ printf("\nWhite Space: %d", countWhite);
+ printf("\nOther Characters: %d\n", countOther);
+
+
+ return 0;
+}
diff --git a/c-book/ch1/exponentiation.c b/c-book/ch1/exponentiation.c
@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int _powerRecurse(int current, int original, int n){
+ if(n == 1){
+ return current;
+ }
+ else{
+ return _powerRecurse(current * original, original, n - 1);
+ }
+}
+
+int power(int m, int n){
+ if(n == 0){
+ return 1;
+ }
+
+ if (n < 0){
+ printf("Negative exponents not supported.\n");
+ exit(-1);
+ }
+
+ return _powerRecurse(m,m,n);
+}
+
+int main(int argc, char** argv){
+
+ if(argc != 3){
+ printf("Usage: exp {base} {exponent}\n");
+ return -1;
+ }
+
+ int base = atoi(argv[1]);
+ int exp = atoi(argv[2]);
+
+ int result = power(base,exp);
+
+ printf("%d^%d = %d\n", base, exp, result);
+
+ return 0;
+}
diff --git a/c-book/ch1/word-length-histogram.c b/c-book/ch1/word-length-histogram.c
@@ -0,0 +1,95 @@
+#include <stdio.h>
+
+#define IN_WORD 0
+#define OUT_WORD 1
+#define MAX_WORD_LENGTH 20
+
+int main(){
+
+ char c;
+ int status = OUT_WORD;
+ int wordLengths [MAX_WORD_LENGTH];
+ int currentLength = 0;
+
+ for(int i = 0 ; i < MAX_WORD_LENGTH; ++i){
+ wordLengths[i] = 0;
+ }
+
+ while((c = getchar()) != EOF){
+ if(status == OUT_WORD){
+ if(c != ' ' && c != '\t' && c != '\n'){
+ status = IN_WORD;
+ currentLength = 1;
+ }
+ }
+ else{
+ if(c == '\t' || c == '\n' || c == ' '){
+ status = OUT_WORD;
+ // if it's too long, just don't count it.
+ if (currentLength < MAX_WORD_LENGTH){
+ wordLengths[currentLength] += 1;
+ }
+
+ }
+ else{
+ currentLength += 1;
+ }
+ }
+
+ }
+
+ if (currentLength != 0){
+ // if it's too long, just don't count it.
+ if (currentLength < MAX_WORD_LENGTH){
+ wordLengths[currentLength] += 1;
+ }
+ currentLength = 0;
+ }
+
+ // horizontal print
+ //for(int i = 0 ; i < MAX_WORD_LENGTH; ++i){
+ // printf("\n%5d: ", i);
+ // for(int x = 0 ; x < wordLengths[i] ; ++x){
+ // printf("x");
+ // }
+ //}
+ //printf("\n");
+
+
+
+ // vertical print
+
+ int max = 0;
+ for(int i = 0 ; i < MAX_WORD_LENGTH; ++i){
+ if(wordLengths[i] > max){
+ max = wordLengths[i];
+ }
+ }
+
+ int current = max;
+
+ for(int i = max ; i > 0; --i){
+ printf("\n");
+ for(int x = 0 ; x < MAX_WORD_LENGTH; ++x){
+ if(wordLengths[x] > i){
+ char p = 'x';
+ printf("%3c", p);
+ }
+ else{
+ char p = ' ';
+ printf("%3c", p);
+ }
+ }
+ }
+ printf("\n");
+
+ for(int x = 0 ; x < MAX_WORD_LENGTH; ++x){
+ printf("%3d", x);
+ }
+
+
+ printf("\n");
+
+
+ return 0;
+}
diff --git a/crypto/frequency-analysis.c b/crypto/frequency-analysis.c
@@ -0,0 +1,48 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char** argv){
+ if(argc != 3){
+ printf("{source-file}");
+ }
+
+ char* source = argv[1];
+
+ FILE* fpSrc = fopen(source, "r");
+
+ fseek(fpSrc, 0, SEEK_END);
+ long fsize = ftell(fpSrc);
+ fseek(fpSrc, 0, SEEK_SET);
+
+ char * fileContents = malloc(fsize + 1);
+ fread(fileContents, fsize, 1, fpSrc);
+ fclose(fpSrc);
+
+ fileContents[fsize] = 0;
+
+ char c;
+ int itr;
+
+ itr = 0;
+ int charCounts [256];
+
+ for(int i = 0 ; i < 256; ++i){
+ charCounts[i] = 0;
+ }
+
+ while((c = fileContents[itr]) != 0){
+ charCounts[c] += 1;
+ itr += 1;
+ }
+
+ for(int i = 0 ; i < 256; ++i){
+ if((i <= 'Z' && i >= 'A') || (i <= 'z' && i >= 'a')){
+ if(charCounts[i] != 0){
+ printf("%5c%5d\n", (char)i, charCounts[i]);
+ }
+ }
+ }
+
+ free(fileContents);
+
+}
