fgets normal input from stdin with stop at newline

C fgets stop at eof and newline

char* inputStringWithStopChar(char stopChar){
    int n = 5;
    int size = n;
    char* const_str = (char*)malloc(n*sizeof(char));
    char* substring = (char*)malloc((n+n)*sizeof(char));
    char*p;
    while((fgets(const_str,n,stdin)!=NULL)&&(strchr(const_str,stopChar)==NULL)){
        strcat(substring,const_str);
        size += n;
        substring = (char*)realloc(substring,size*sizeof(char));
        }
    strcat(substring,const_str);
    size += n;
    substring = (char*)realloc(substring,size*sizeof(char));
    /*
    printf("<%s> is \n",const_str);
    printf("%s is \n",substring);
    printf("%d is \n",size);
    */
    if ((p=strchr(substring,stopChar))!=NULL){
        p[0]='\0';
    }
    if(feof(stdin)){
        changeToFull();
    }
    return substring;
}

C: fgets stop at eof and newline

char* inputString(){
    int n = 5;
    int size = n;
    char* const_str = (char*)malloc(n*sizeof(char));
    char* substring = (char*)malloc((n+n)*sizeof(char));
    char*p;
    while((fgets(const_str,n,stdin)!=NULL)&&(strchr(const_str,'\n')==NULL)){
        strcat(substring,const_str);
        size += n;
        substring = (char*)realloc(substring,size*sizeof(char));
        }
    strcat(substring,const_str);
    size += n;
    substring = (char*)realloc(substring,size*sizeof(char));
    /*
    printf("<%s> is \n",const_str);
    printf("%s is \n",substring);
    printf("%d is \n",size);
    */
    if ((p=strchr(substring,'\n'))!=NULL){
        p[0]='\0';
    }
    if(feof(stdin)){
        changeToFull();
    }
    return substring;
}

it is the best, that i ever seen in internet. (can be changed to any symbol, if you change '\n' to )