printf() 函数

请求printf()打印变量的指令取决于变量的类型。下图来自C Primer Puls.

 以下为简单的测试代码：

#include<stdio.h>

#define PI 3.1415923

int main()
{
    int num = 5;
    int cost = 3100;
    float exp = 13.5;
    printf("the num is %d\n,the  exp is %f\n",num,exp);
    printf("%d * %d = %d\n",num,cost,num*cost);
    printf("this is a character [%c]\n",'A');
    printf("this is a string [%s]\n","hello world");
    return 0;
}

print的转换说明修饰符和标志：

 

 以下为简单的测试代码：

#include<stdio.h>
#define WIDTH 258 

int main()
{
    const double RENT = 9527.66;
    printf("*%d*\n",WIDTH);
    printf("*%4d*\n",WIDTH);
    printf("*%-6d*\n",WIDTH);
    printf("*%-5d*\n",WIDTH);
    printf("\n\n"); 
    printf("*%f*\n",RENT);
    printf("*%e*\n",RENT);
    printf("*%4.2f*\n",RENT);
    printf("*%3.1lf*\n",RENT);

    printf("*%10.3f*\n",RENT);
    printf("*%10.3e*\n",RENT);
    printf("*%+4.2f*\n",RENT);
    printf("*%010.2f*\n",RENT);
    return 0;
}