Question

How to find the first non-repeated character in a string with C

Answer 1

#include <stdio.h>

char getFirstNonRepeatedCharacter(char *s) { 
    int ascii_count[256]; 
 
    int i; 
    for (i = 0; *(s+i); i++) 
        if (*(s+i)!=' ') 
            ascii_count[(int)*(s+i)]++; 
     
    int n = i; 
    
    for (i = 0; i < n; i++) 
        if (ascii_count[(int)*(s+i)] == 1) 
            return s[i]; 
     
    return ' ';
} 
    
 
int main(int argc, char **argv) 
{
    char s[] = "c c programming"; 
      
    char ch = getFirstNonRepeatedCharacter(s); 
      
    printf("%c\n", ch);
      
    return 0; 
}
   
 
  
/*
run:
    
p
    
*/

 

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Answer 2

#include <stdio.h>
 
#define SIZE 256
 
void count_occurrences(char s[], char occurrences[]) {
    int i = 0;
    while (s[i]) {
        occurrences[(int)s[i]]++;
        i++;
    }
}
 
int main() {
    char s[] = "c c++ csharp java php python";
    char occurrences[SIZE] = { 0 };
 
    count_occurrences(s, occurrences);
 
    int i = 0;
    while (s[i]) {
        if (occurrences[(int)s[i]] == 1) {
            printf("%c", s[i]);
            break;
        }
        i++;
    }
 
    return 0;
}
 
 
 
/*
run:
 
s
 
*/

 

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