c utils

#include <stdio.h>
int len(char text[]){
    int i;
    for( i = 0 ; text[i] ; ++i );
    return i;
}

char upper(char c){
    if( c < 97 || c > 122 ) return c;
    return c-32;
}

char lower(char c){
    if( c < 65 || c > 90 ) return c;
    return c+32;
}

void sUpper(char text[]){
    int i;
    for( i = 0 ; i < len(text) ; ++i ){
        text[i] = upper(text[i]);
    }
}

void sLower(char text[]){
    int i;
    for( i = 0 ; i < len(text) ; ++i ){
        text[i] = lower(text[i]);
    }
}

void sReverse(char text[]){
    char output[len(text)];
    int i, idx = len(text);

    output[idx--] = '\0';

    for( i = 0 ; text[i] ; ++i )
        output[idx--] = text[i];
    for( i = 0 ; text[i] ; ++i )
        text[i] = output[i];
}

void sSort(char text[], int reverse){
    //using counting sort
    char output[len(text)];
    int count[256] = {0};
    int i;

    for( i = 0 ; text[i] ; ++i )
        ++count[text[i]];

    for( i = 1 ; i <= 255 ; ++i )
        count[i] += count[i-1];

    for( i = 0 ; text[i] ; ++i ){
        output[count[text[i]]-1] = text[i];
        --count[text[i]];
    }

    for( i = 0 ; text[i] ; ++i )
        text[i] = output[i];
    if(reverse)
        sReverse(text);
}

int isAnagram(char a[], char b[], int insensitive){
    if( len(a) != len(b) ) return 0;
    if( insensitive ){
        sUpper(a);
        sUpper(b);
    }
    sSort(a, 0);
    sSort(b, 0);
    int i;
    for( i = 0 ; a[i] ; ++i )
        if( a[i] != b[i] ) return 0;
    return 1;
}

int main(){
    char x[] = "abAB";
    sSort(x, 0);
    printf("%s\n", x);
    return 0;
}