C - 如何读取长度未知的字符串

这是我的代码:

int main() {
    int i=0;
    int size=1;
    char *pntName=NULL;//a pointer to an array of chars.
    pntName = (char*) malloc(size *sizeof(char));//allocate sapce for the first char. 
    while(pntName[size-1]!=':'){
        if(pntName!=NULL)//check the case couldn't allocate 
           printf("Error");
        else{
            if(i

我正在尝试读取包含名称的字符串.用户可以输入字符直到他输入':'.我的代码出了什么问题？


1> user3121023..：
字符串需要终止,'\0'因此允许额外的字符.重新分配时,最好在重新分配失败时使用另一个指针.

#include 
#include 

int main(void) {
    int i=0;
    int size=1;
    char *pntName=NULL;//a pointer to an array of chars.
    char *temp=NULL;//a temporary pointer

    pntName = malloc( size + 1);//allocate space for two char one for the '\0' to terminate the string
    while(1){
        size++;
        temp = realloc(pntName, size + 1);//reallocat space.
        if ( temp == NULL) {
            printf ( "error allocating memory");
            free ( pntName);
            return 1;
        }
        pntName = temp;
        if ( ( scanf("%c",&pntName[i])) == 1) {
            i++;
            pntName[i] = '\0'; // terminate the string
            if ( pntName[i-1] == ':') {
                break;
            }
        }
        else {
            break;
        }
    }
    printf ( "\n%s\n", pntName);
    free ( pntName);// release memory
    return 0;
}