Add example with string public input

Author: makxenov

examples/CMakeLists.txt

@@ -74,3 +74,4 @@ add_example(pallas_curve_addition_example
 #            SOURCES pallas_curve_examples/pallas_curve_mul_add.cpp
 #            INPUT pallas_curve_examples/pallas_curve_mul_add.inp)
 add_example(ed25519_curve_add SOURCES ed25519_curve_add.cpp INPUT ed25519_curve_add.inp)
+add_example(strlen_example SOURCES strlen.cpp INPUT strlen.inp)

examples/strlen.cpp

@@ -0,0 +1,6 @@
+#include <cstddef>
+[[circuit]] size_t strlen(const char *str) {
+    size_t counter = 0;
+    while (str[counter++] != '\0');
+    return counter - 1;
+}

examples/strlen.inp

@@ -0,0 +1 @@
+[ {"string": "abcdefgh"}]