Implement random.randrange()

Author: namannimmo10

src/runtime/impure/lfortran_intrinsics.c

@@ -35,6 +35,12 @@ LFORTRAN_API float _lfortran_random_float()
     return ((float) rand() / (float) RAND_MAX);
 }
 
+LFORTRAN_API int _lfortran_randrange(int lower, int upper)
+{
+    int rr = lower + (rand() % (upper - lower));
+    return rr;
+}
+
 LFORTRAN_API int _lfortran_random_int(int lower, int upper)
 {
     int randint = lower + (rand() % (upper - lower + 1));

src/runtime/impure/lfortran_intrinsics.h

@@ -32,6 +32,7 @@ typedef double _Complex double_complex_t;
 LFORTRAN_API double _lfortran_sum(int n, double *v);
 LFORTRAN_API void _lfortran_random_number(int n, double *v);
 LFORTRAN_API float _lfortran_random_float();
+LFORTRAN_API int _lfortran_randrange(int lower, int upper);
 LFORTRAN_API int _lfortran_random_int(int lower, int upper);
 LFORTRAN_API void _lfortran_printf(const char* format, ...);
 LFORTRAN_API void _lfortran_complex_add(struct _lfortran_complex* a,

src/runtime/random.py

@@ -11,6 +11,16 @@ def random() -> f64:
 def _lfortran_random_float() -> f64:
     pass
 
+def randrange(lower: i32, upper: i32) -> i32:
+    """
+    Return a random integer N such that `lower <= N < upper`.
+    """
+    return _lfortran_randrange(lower, upper)
+
+@ccall
+def _lfortran_randrange(lower: i32, upper: i32) -> i32:
+    pass
+
 def randint(lower: i32, upper: i32) -> i32:
     """
     Return a random integer N such that `lower <= N <= upper`.