Question

How to sort by strings a mixed pair of string and number elements in an array with C

Answer 1

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void extract_name(const char *s, char *out) {
    const char *p = strrchr(s, ' ');   // find last space
    size_t len = p - s;                // length of the name part
    strncpy(out, s, len);
    out[len] = '\0';
}

int cmp(const void *a, const void *b) {
    const char *sa = *(const char **)a;
    const char *sb = *(const char **)b;

    char nameA[100], nameB[100];
    extract_name(sa, nameA);
    extract_name(sb, nameB);

    return strcmp(nameA, nameB);
}

int main(void) {
    const char *arr[] = {
        "Python 4", "C 9", "C++ 5", "C# 6",
        "Java 1", "PHP 7", "Go 2"
    };

    size_t n = sizeof(arr) / sizeof(arr[0]);

    qsort(arr, n, sizeof(char *), cmp);

    for (size_t i = 0; i < n; i++)
        printf("%s\n", arr[i]);

    return 0;
}



/*
run:

C 9
C# 6
C++ 5
Go 2
Java 1
PHP 7
Python 4

*/

 

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