feat: add reamde file

Author: Lokeshranjan8

lib/node_modules/@stdlib/stats/base/dists/beta/cdf/README.md

@@ -2,7 +2,7 @@
 
 @license Apache-2.0
 
-Copyright (c) 2018 The Stdlib Authors.
+Copyright (c) 2026 The Stdlib Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -160,6 +160,114 @@ logEachMap( 'x: %0.4f, α: %0.4f, β: %0.4f, F(x;α,β): %0.4f', x, alpha, beta,
 
 <!-- /.examples -->
 
+<!-- C interface documentation. -->
+
+* * *
+
+<section class="c">
+
+## C APIs
+
+<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<!-- C usage documentation. -->
+
+<section class="usage">
+
+### Usage
+
+```c
+#include "stdlib/stats/base/dists/beta/cdf.h"
+```
+
+#### stdlib_base_dists_beta_cdf( x, alpha, beta )
+
+Returns the [differential cdf][cdf] of a [beta][beta-distribution] distribution with parameters `alpha` (first shape parameter) and `beta` (second shape parameter).
+
+```c
+double y = stdlib_base_dists_beta_cdf( 0.5, 1.0, 1.0 );
+// returns 0.5
+```
+
+The function accepts the following arguments:
+
+-   **x**: `[in] double` input value.
+-   **alpha**: `[in] double` first shape parameter.
+-   **beta**: `[in] double` second shape parameter.
+
+```c
+double stdlib_base_dists_beta_cdf( const double x, const double alpha, const double beta );
+```
+
+</section>
+
+<!-- /.usage -->
+
+<!-- C API usage notes. Make sure to keep an empty line after the `section`
+element and another before the `/section` close. -->
+
+<section class="notes">
+
+</section>
+
+<!-- /.notes -->
+
+<!-- C API usage examples. -->
+
+<section class="examples">
+
+### Examples
+
+```c
+#include "stdlib/stats/base/dists/beta/cdf.h"
+#include "stdlib/constants/float64/eps.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+static double random_uniform( const double min, const double max ) {
+    double v = (double)rand() / ( (double)RAND_MAX + 1.0 );
+    return min + ( v*(max-min) );
+}
+
+int main( void ) {
+    double alpha;
+	double beta;
+	double x;
+	double y;
+	int i;
+
+    for ( i = 0; i < 10; i++ ) {
+		alpha = random_uniform( STDLIB_CONSTANT_FLOAT64_EPS, 5.0 );
+		beta = random_uniform( STDLIB_CONSTANT_FLOAT64_EPS, 5.0 );
+		x = random_uniform( 0.0, 1.0 );
+		y = stdlib_base_dists_beta_cdf( x, alpha, beta );
+		printf( "x: %lf, α: %lf, β: %lf, F(x;α,β): %lf\n", x, alpha, beta, y );
+	}
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+</section>
+
+<!-- /.c -->
+
+<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="references">
+
+</section>
+
+<!-- /.references -->
+
 <!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
 
 <section class="related">