First Non-Repeating Character in String

altruistcoder · altruistcoder · commit 504f7c47170c · 2019-05-25T01:22:12.000+05:30
diff --git a/README.md b/README.md
@@ -102,3 +102,8 @@ This is a repository containing various C++ Programs to understand the basic con
 
   C++ Code for finding the second largest element present in the given array.
 
+* [First Non-Repeating Character in an String](https://github.com/altruistcoder/Data-Structures-Python/blob/master/first_non_repeating_character.cpp):
+
+  C++ Code for finding the first non-repeating character present in the given string.
+
+
diff --git a/first_non_repeating_character.cpp b/first_non_repeating_character.cpp
@@ -0,0 +1,33 @@
+# include<iostream>
+#define NO_OF_CHARS 256
+using namespace std;
+
+int firstNonRepeating(char *str)
+{
+    int i;
+    int *freq = new int[NO_OF_CHARS];
+    for(i=0; *(str+i); i++)
+        freq[*(str+i)]++;
+    cout<<endl;
+    for(i=0; *(str+i); i++)
+    {
+        if(freq[*(str+i)] == 1)
+        {
+            return i;
+        }
+    }
+    return -1;
+}
+
+int main()
+{
+    char str[256];
+    cout<<"Enter a string: ";
+    cin>>str;
+    int r = firstNonRepeating(str);
+    if(r == -1)
+        cout<<"No non-repeating character present in given string. Either all of the characters are repeating or string is empty";
+    else
+        cout<<"First non-repeating character present in given string: "<<str[r];
+    return 0;
+}
