Added C code of GCD (#26779)

* Added C code of GCD

* fix: correct code format syntax

guide/english/algorithms/greatest-common-divisor-euclidean/index.md

@@ -65,6 +65,27 @@ function gcd(a, b) {
 }
 ```
 
+C code to perform GCD using recursion
+```c
+int gcd(int a, int b) 
+{ 
+    // Everything divides 0  
+    if (a == 0) 
+       return b; 
+    if (b == 0) 
+       return a; 
+  
+    // base case 
+    if (a == b) 
+        return a; 
+  
+    // a is greater 
+    if (a > b) 
+        return gcd(a-b, b); 
+    return gcd(a, b-a); 
+}
+```
+
 C++ Code to Perform GCD-
 ```csharp
 int gcd(int a,int b) {