Started work on C arithmetic progressions

arithmetic_progressions/.gitignore

@@ -0,0 +1 @@
+ap

arithmetic_progressions/Makefile

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+# Rudimetary makefile
+CC=gcc
+CFLAGS= -ggdb 
+
+ap: arithmetic_progressions.c
+	$(CC) -o $@ $< $(CFLAGS)
+
+clean:
+	rm ap

arithmetic_progressions/arithmetic_progressions.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define INTS_START_SIZE 8
+#define INTS_DELIM " \t\n"
+#define BUF_SIZE 1024
+
+size_t read_ints(char *str, int **ints) {
+    if (str == NULL) {
+        return 0;
+    }
+    size_t size = INTS_START_SIZE;
+    *ints = malloc(INTS_START_SIZE * sizeof *ints);
+    if (*ints == NULL) {
+        return 0;
+    }
+
+    size_t i = 0;
+    char *toksave, *end;
+    long int tmp;
+    char *tok = strtok_r(str, INTS_DELIM, &toksave);
+    while (tok != NULL) {
+        tmp = strtol(tok, &end, 10);
+        if (*end == '\0' || isspace(*end)) { // valid number found
+            if (i == size) {
+                // If we have filled array, double its size
+                size *= 2;
+                *ints = realloc(*ints, size * sizeof *ints);
+                if (*ints == NULL) {
+                    return 0;
+                }
+            }
+            // store in array
+            (*ints)[i] = tmp;
+            i++;
+        }
+        tok = strtok_r(NULL, INTS_DELIM, &toksave);
+    }
+    return i;
+}
+
+int main(int argc, char **argv) {
+    char buf[BUF_SIZE];
+    fgets(buf, BUF_SIZE, stdin);
+    int *ints;
+    size_t numints =  read_ints(buf, &ints);
+    int i;
+    for (i = 0; i < numints; i++) {
+        printf("%d\n", ints[i]);
+    }
+    return 0;
+}