问函数返回导致顶级大小损坏的字符串。

EN

#include "externalLibrary.h"
#include <ctype.h>
#include <malloc.h>
#include <assert.h>
#include <string.h>

char * restrict externalLibrary_Clean(const char* restrict input) {
    // first we define the return value as a pointer and initialize
    // an integer to count the length of the string
    char * returnVal = malloc(sizeof(input));
    char * initialReturnVal = returnVal; //point to the start location

    // until we hit the end of the string, we use this while loop to
    // iterate through it
    while (*input != '\0') {
        if (isalpha(*input)) {  // if we encounter an alphabet character (a-z/A-Z)
                                // then we convert it to an uppercase value and point our return value at it
            *returnVal = toupper(*input);
            returnVal++; //we use this to move our return value to the next location in memory
            
        }
        input++; // we move to the next memory location on the provided character pointer
    }

    *returnVal = '\0'; //once we have exhausted the input character pointer, we terminate our return value

    return initialReturnVal;
}

int * restrict externalLibrary_getFrequencies(char * ar, int length){
    static int freq[26];
    for (int i = 0; i < length; i++){
        freq[(ar[i]-65)]++;
    }
    return freq;
}

#ifndef LEARNINGC_EXTERNALLIBRARY_H
#define LEARNINGC_EXTERNALLIBRARY_H

#ifdef __cplusplus
extern "C" {
#endif

char * restrict externalLibrary_Clean(const char* restrict input);
int * restrict externalLibrary_getFrequencies(char * ar, int length);

#ifdef __cplusplus
}
#endif

#endif //LEARNINGC_EXTERNALLIBRARY_H

#include <stdio.h>
#include "externalLibrary.h"

int main() {
    char * unfilteredString = "ASDFOIWEGOASDGLKASJGISUAAAA";//if this exceeds 26 characters, the program breaks 
    char * cleanString = externalLibrary_Clean(unfilteredString);
    //int * charDist = externalLibrary_getFrequencies(cleanString, 25); //this works just fine... for now

    printf("\nOutput: %s\n", unfilteredString);
    printf("\nCleaned Output: %s\n", cleanString);
    /*for(int i = 0; i < 26; i++){
        if(charDist[i] == 0){

        }
        else {
            printf("%c: %d \n", (i + 65), charDist[i]);
        }
    }*/

    return 0;
}