diff --git a/C/Advance/calculator.c b/C/Advance/calculator.c
new file mode 100644
index 0000000..58c8132
--- /dev/null
+++ b/C/Advance/calculator.c
@@ -0,0 +1,163 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#define N 100
+ 
+void pp(char v[][20])
+{
+  int             i;
+  puts("---------------");
+  for (i = 0; *v[i]; i++)
+    printf("%s, ", v[i]);
+  puts("\n---------------");
+}
+ 
+double calc(char *s)
+{
+  char           *w = malloc(N), *p, *p2, v[N][20];
+  int             i, diff;
+  double          acc;
+ 
+  /* ()calc */
+  while ((p = strchr(s, ')'))) {
+    p2 = p + 1;
+    *p = '\0';
+    while (*p != '(')
+      p--;
+    *p = '\0';
+    sprintf(w, "%s %g %s", s, calc(p + 1), p2);
+    sprintf(s, "%s", w);
+  }
+ 
+  /* tokenize */
+  i = 0;
+  sscanf(s, "%s", v[i]);
+  p = strtok(s, " ");
+  while (p) {
+    sprintf(v[i], "%s", p);
+    p = strtok(NULL, " ");
+    i++;
+  }
+  sprintf(v[i], "%s", "");
+ 
+  /* log calc */
+  for (i = 0; *v[i]; i++) {
+    if (strcmp("log", v[i]) == 0) {
+      sprintf(v[i], "%g", log10(atof(v[i + 1])));
+      sprintf(v[i + 1], " ");
+    }
+  }
+ 
+  /* sin calc */
+  for (i = 0; *v[i]; i++) {
+    if (strcmp("sin", v[i]) == 0) {
+      sprintf(v[i], "%g", sin(atof(v[i + 1]) / 180 * M_PI));
+      sprintf(v[i + 1], " ");
+    }
+  }
+ 
+  /* cos calc */
+  for (i = 0; *v[i]; i++) {
+    if (strcmp("cos", v[i]) == 0) {
+      sprintf(v[i], "%g", cos(atof(v[i + 1]) / 180 * M_PI));
+      sprintf(v[i + 1], " ");
+    }
+  }
+ 
+  /* tan calc */
+  for (i = 0; *v[i]; i++) {
+    if (strcmp("tan", v[i]) == 0) {
+      sprintf(v[i], "%g", tan(atof(v[i + 1]) / 180 * M_PI));
+      sprintf(v[i + 1], " ");
+    }
+  }
+ 
+  /* compact */
+  diff = 0;
+  for (i = 0; *v[i]; i++) {
+    if (*v[i] == ' ')
+      diff++;
+    if (diff && *v[i] != ' ')
+      sprintf(v[i - diff], "%s", v[i]);
+  }
+  sprintf(v[i - diff], "%s", "");
+ 
+  /* - calc */
+  for (i = 0; *v[i]; i++) {
+    if (strcmp("-", v[i]) == 0) {
+      sprintf(v[i], "+");
+      sprintf(v[i + 1], "%g", -atof(v[i + 1]));
+    }
+  }
+ 
+  /* / calc */
+  for (i = 0; *v[i]; i++) {
+    if (strcmp("/", v[i]) == 0) {
+      sprintf(v[i], "*");
+      sprintf(v[i + 1], "%g", 1 / atof(v[i + 1]));
+    }
+  }
+ 
+  /* * calc */
+  for (i = 0; *v[i]; i++) {
+    if (strcmp("*", v[i]) == 0) {
+      sprintf(v[i], " ");
+      sprintf(v[i + 1], "%g", atof(v[i - 1]) * atof(v[i + 1]));
+      sprintf(v[i - 1], "0");
+    }
+  }
+ 
+  /* pp(v); */
+ 
+  /* + calc */
+  acc = 0;
+  for (i = 0; *v[i]; i++)
+    acc += atof(v[i]);
+  return acc;
+}
+ 
+char *insertBlank(char *s)
+{
+  char           *w = malloc(N);
+ 
+  *w = '\0';
+  while (*s) {
+    if (strchr("+-*/()", *s)) {
+      strcat(w, " ");
+      strncat(w, s, 1);
+      strcat(w, " ");
+    } else {
+      strncat(w, s, 1);
+    }
+    s++;
+  }
+ 
+  return w;
+}
+ 
+ 
+double dentaku(char *s)
+{
+  return calc(insertBlank(s));
+}
+ 
+int main(int argc,char**argv) {
+ 
+  char           *s[] = {
+    "2  +  5  /  5  +  4   *   2   +   1",
+    "2 * 3 + 1",
+    "( 2 + 3 ) * 7 * ( 3 - 1 )",
+    "sin(90) * 2 + 1 - 2",
+    "log(3) * 2 + 1",
+    "1-2*(3+1)-2",
+    "log(log(123))",
+    "log log 123",
+    "1+(  log(2 *sin (5*log (2)+1)/2)+3*4)"
+  };
+  int i;
+  for (i = 0; i<9; i++)
+    printf("input = %s\nresult = %g\n\n", s[i], dentaku(s[i]));
+ 
+  return 0;
+}