Question

How to print characters that have even frequencies of occurrence in a string with C

Answer 1

#include <stdio.h>
#include <string.h>
#include <ctype.h>
   
void print_even_frequencies_char(char s[]) { 
    int letters[256] = {0}; 
    
    for (int i = 0; i < strlen(s); i++) {
         if (isalpha(s[i]))
             letters[(int)s[i]]++;
    }
    
    for (int i = 0; i < 256; i++) { 
        if (letters[i] != 0 && letters[i] % 2 == 0) {
            printf("%c %d\n", (char)i, letters[i]);
        }
    } 
} 
int main() 
{                       
    char s[] = "c programming pro oo"; 
       
    print_even_frequencies_char(s);
        
    return 0; 
} 
     
     
     
/*
run:
     
g 2
m 2
o 4
p 2
     
*/

 

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