solve 8

1 files changed, 58 insertions, 0 deletions

diff --git a/0008/main.c b/0008/main.c
new file mode 100644
index 0000000..c229dd7
--- /dev/null
+++ b/0008/main.c
@@ -0,0 +1,58 @@
+#include <ctype.h>
+#include <stdint.h>
+#include <stdio.h>
+
+char * skip_space(char *s) {
+    while (isspace(*s)) s++;
+    return s;
+}
+
+int symbol(char **ps) {
+    char *s = *ps;
+    if (*s == '+') {
+        s++;
+        *ps = s;
+        return 1;
+    }
+    if (*s == '-') {
+        s++;
+        *ps = s;
+        return -1;
+    }
+    return 1;
+}
+
+int64_t read_num(char *s) {
+    int64_t r = 0;
+    int i = 0;
+    while (1) {
+        if (s[i] < '0' || s[i] > '9') {
+            return r;
+        }
+        r = r * 10 + s[i] - '0';
+        if (r > ((int64_t)1 << 32)) {
+            return r;
+        }
+        i++;
+    }
+    return r;
+}
+
+int myAtoi(char* s) {
+    s = skip_space(s);
+    int sym = symbol(&s);
+    int64_t r = read_num(s);
+    if (sym > 0) {
+        if (r > 2147483647) r = 2147483647;
+    } else {
+        if (r > 2147483648) r = 2147483648;
+    }
+    return sym > 0 ? r : -r;
+}
+
+int main() {
+    printf("%d\n", myAtoi("123"));
+    printf("%d\n", myAtoi("  +123"));
+    printf("%d\n", myAtoi("0000000000012345678"));
+    printf("%d\n", myAtoi("-123111111111111111"));
+}
\ No newline at end of file