first commit!

atof.c

@@ -0,0 +1,48 @@
+#include <ctype.h>
+#include <stdio.h>
+
+#define MAXLINE 100
+
+int getlime(char s[], int lim)
+{
+  int ch, i;
+  for (i = 0; i < lim - 1 && (ch = getchar()) != EOF && ch != '\n'; ++i)
+      s[i] = ch;
+  if (ch == '\n') {
+    s[i] = ch;
+    ++i;
+  }
+  s[i] = '\0';
+  return i;
+}
+
+double atof(char s[]) {
+  double val, power;
+  int ind, sign;
+
+  for (ind = 0; isspace(s[ind]); ++ind) /* skip whitespace */
+    ;
+  sign = (s[ind] == '-') ? -1 : 1;
+  if (s[ind] == '+' || s[ind] == '-')
+    ++ind;
+
+  for (val = 0.0; isdigit(s[ind]); ++ind)
+    val = 10 * val + (s[ind] - '0');
+  if(s[ind] == '.')
+    ++ind;
+  for (power = 1.0; isdigit(s[ind]); ++ind) {
+    val = 10.0 * val + (s[ind] - '0');
+    power *= 10;
+  }
+  return sign * val / power;
+}
+
+int main() {
+  double sum = 0;
+  char line[MAXLINE];
+
+  while (getlime(line, MAXLINE) > 0)
+    printf("\t%g\n", sum += atof(line));
+
+  return 0;
+}