error: invalid conversion from ‘const char*’ to ‘char*’ [-fpermissive]

[운영자]

error: invalid conversion from ‘const char*’ to ‘char*’ [-fpermissive]

-> const를 붙이거나 난 무조건 const char *가아닌 그냥 char *로 받아야 한다면,  #include <string.h>를 #include <cstring>로 변경해주세요.

권장하는 것은 아니지만, 정 안 되면 그냥 구현해서 사용하면 됩니다:

char *mystrrchr(const char *s, int ch)
{
    char *start = (char *) s;

    while (*s++);
    while (--s != start && *s != (char) ch);
    if (*s == (char) ch) return (char *) s;

    return NULL;
}

char *mystrchr(const char *str, int c) {
        while (*str != '\0') {
                if (*str == c) {
                        return (char *)str;
                }
                str++;
        }
        return NULL;
}

int mystrlen(char *s) {
        char *p = s;
        while (*p++ != '\0');

        return p - s;
}

char *mystrstr(const char *s1, const char *s2){
    int i;

    if(*s2=='\0')
        return (char *)s1;

    else{
        for(;*s1;s1++){
            if(*s1==*s2){

                for(i=1;*(s1+i)==*(s2+i);i++);

                if(i==mystrlen((char *)s2))
                    return (char *)s1;
            }
        }
        return NULL;
    }
}