C語言筆記

 

函數	說明
gcvt()	將浮點型數轉換爲字符串(四捨五入)
index()	查找字符串並返回首次出現的位置
rindex()	查找字符串並返回最後一次出現的位置
strcasecmp()	判斷字符串是否相等(忽略大小寫)
strcpy()	複製字符串
strdup()	複製字符串
strncasecmp()	比較字符串的前n個字符

 

http://www.cnblogs.com/Shirlies/p/4282182.html

 

1. 打開文件

int openFile1(void)
{
    FILE *file;
    int ch;
    if((file=fopen("test.txt", "r")) == NULL)
    {
        printf("the file can't be opened!\n");
        exit(1);
    }

     //int fgetc(FILE *stream); 將把由流指針指向的文件中的一個字符讀出    
    while((ch=fgetc(file)) != EOF)
    {
        putchar(ch);
        //fputc(ch,stdout);
    }
    
    if(fclose(file) == 0)
    {
        printf("Succeed closed!\n");
    }
    
    //關閉多個文件，fcloseall()
    //fcloseall();
    
    return 0;
}

int openFile2(void)
{
    FILE *file;
    char str[128];
    
    if((file=fopen("test.txt", "r")) == NULL)
    {
        printf("the file can't be opened!\n");
        exit(1);
    }
    
    while(!feof(file))
    {
        if(fgets(str,2,file)!=NULL)
        printf("%s\n", str);
    }
        
    if(fclose(file)!=0) {  
        printf("File cannot be closed\n");   
        exit(1);   
    }   
    else  
        printf("File is now closed\n"); 
}