c-programming

commit 00a927d51f767a45f4e9fa752cc6ab49c830789f
parent 2bb437333b8f37d898cf46bc5adedcd11c891d1c
Author: Andrew Laack <andrew@laack.co>
Date:   Fri, 17 Oct 2025 22:52:51 -0500

Fahrenheit with symbolic constants

Diffstat:
A
c-book/ch1/fahrenheit2.c
 | 
44
++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 44 insertions(+), 0 deletions(-)
diff --git a/c-book/ch1/fahrenheit2.c b/c-book/ch1/fahrenheit2.c
@@ -0,0 +1,44 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define FALLBACK_LOWER 0
+#define FALLBACK_UPPER 100
+#define FALLBACK_STEP 10
+
+float celsius(int fahr){
+    return (fahr - 32) * (5.0 / 9.0);
+}
+
+
+int main(int argc, char** argv){
+
+
+    int lower, upper, step;
+
+    lower = FALLBACK_LOWER;
+    upper = FALLBACK_UPPER;
+    step = FALLBACK_STEP;
+
+    if (argc >= 2){
+        lower = atoi(argv[1]);
+    }
+    if (argc >= 3){
+        upper = atoi(argv[2]);
+    }
+    if (argc >= 4){
+        step = atoi(argv[3]);
+    }
+    if (argc >= 5){
+        printf("Too many arguments. Usage: fahr {lower} {upper} {step}\n");
+        return -1;
+    }
+
+    if (step <= 0){
+        printf("Positive steps only\n");
+        return -1;
+    }
+
+    for(int fahr = lower; fahr < upper ; fahr += step){
+        printf("%5d %6.1f\n", fahr, celsius(fahr));
+    }
+}