输入输出函数 printf/scanf

1.

字符串，整数，浮点数的打印

    /*
     * print.c
     *
     * function: generate some simple output
     *
     * 2011-10-26 by YourName
     *
     */


    #include <stdio.h>

    int main(int argc, char *argv[])
    {
            int i = 10;
            float num = 3.14;

            //print string
            printf("Hello world!\n");

            //print a integer
            printf("i = %d\n", i);

            //print a hexadecimal number
            printf("i = 0x%x\n", i);

            //floating point numbers
            printf("num = %f\n", num);

            return 0;
    }

2.

printf()中格式控制符的使用

    /*
     * filename: printf_advan.c
     *
     * function: printf()
     *
     * author: YourName
     *
     * version: 0.1
     *
     * data: 2011-10-26
     *
     *
     * */


    #include <stdio.h>


    int main(int argc, char *argv[])
    {

            printf("%d, 0x%x, %f\n", 100, 100, (double)100);
            printf("%%, ', \"\n");
            printf("sizeof(char) = %d\n", sizeof(char));
            printf("sizeof(int) = %d\n", sizeof(int));

            return 0;
    }

3.

数据读取，scanf()的使用

    /*
     * scanf.c
     *
     * function: scanf()
     *
     * 2011-10-26 by YourName
     *
     */


    #include <stdio.h>

    int main(int argc, const char *argv[])
    {
            int i, j, k;
            char str[100];

            //input a integer
            printf("Please input a integer:");
            scanf("%d", &i);
            printf("%d\n", i); 

            //input some integers
            printf("Please input 3 integers:");
            scanf("%d %d %d", &i, &j, &k);
            printf("i = %d, j = %d, k = %d\n", i, j, k);

            //input a string 
            printf("Please input a string:");
            scanf("%s", str);
            printf("%s\n", str);

            return 0;
    }

4.

使用scanf()接收不含空格的字符串

    #include <stdio.h>

    #define N 1024

    int main(int argc, const char *argv[])
    {
            char str[N];

            printf("Please enter <hello world>: ");
            scanf("%s", str);
            printf("%s\n", str);

            return 0;
    }

5.

gets函数接收含有空格的字符串

    #include <stdio.h>

    #define N 1024

    int main(int argc, const char *argv[])
    {
            char str[N];

            printf("Please enter <hello world>: ");
            gets(str);
            printf("%s\n", str);

            return 0;
    }

6.

格式匹配输入数据

    /*
     * filename: y_m_d.c
     *  
     * function: input mm/dd/yy,output yy/mm/dd
     *
     * author: YourName
     *
     * version: 0.1
     *
     * data: 2011-10-26
     */

    #include <stdio.h>


    int main(int argc, char *argv[])
    {
            int year, month, day;

            printf("Enter a date(mm/dd/yyyy):");
            scanf("%d/%d/%d", &month, &day, &year);
            printf("You enterd the date:%4d/%02d/%02d\n", year, month, day);

            return 0;
    }