Occurrence checking of vowels in string program

Author: dev-kant-kumar

string8.c

@@ -0,0 +1,26 @@
+// Write a function to count the occurrence of vowels in a string.
+#include<stdio.h>
+#include<string.h>
+void occurrence(char str[]);
+int main()
+ {
+    char str[100];
+    printf("Enter your string : ");
+    fgets(str,100,stdin);
+    occurrence(str);
+    return 0;
+ }
+void occurrence(char str[])
+ {
+    int count=0;
+    strlwr(str);
+    for(int i=0;i<strlen(str);i++)
+     {
+        if(str[i]=='a' || str[i]=='e' || str[i]=='i' || str[i]=='o' || str[i]=='u')
+         {
+            count++;
+         }
+
+     }
+    printf("Entered string contains %d vowels \n",count); 
+ }