数据类型与表达式的代码练习

//代码清单4-1
#import <Foundation/Foundation.h>

int main(int argc，char *argv[])
{
    @autoreleasepool{
        int a=100;
        float b=331.79;
        double c=8.25+12;
        char d='W';

        NSLog(@"%i",a);//100
        NSLog(@"%f",b);//331.790009
        NSLog(@"%e",c);//8.250000e+12
        NSLog(@"%g",c);//8.25e+12
        NSLog(@"%c",d);//W
    }
}

//代码清单4-4
#import <Foundation/Foundation.h>
int main(int argc,char *argv[])
{
    @autoreleasepool{
        int a=25,b=5,c=10,d=7;
        NSLog(@"a%%b=%i",a%b);//a%b=0
    }
    return 0;
}

//代码清单4-5 类型转换
#import <Foundation/Foundation.h>

int main(int argc,char *argv[])
{
    @autoreleasepool{
        float f1=123.125,f2;
        int i1,i2=-150;

        i1=f1;//浮点数到整数的转换
        NSLog(@"%f to %i",f1,i1);//123

        f1=i2;//整数到浮点数的转换
        NSLog(@"%i to %f",i2,f1);//-150.000000

        f2=i2/100;//整数除以整数
        NSLog(@"%i divided by 100.0 produces %f",i2,f2);//-1.000000

        f2=i2/100.0;//整数除以浮点数
        NSLog(@"%i divided by 100.0 produces %f",i2,f2);//-1.500000

        f2=(float)i2/100;//类型强制转换运算符
        NSLog(@"(float) %i divided by 100 produces %f",i2,f2);//-1.500000
    }
    return 0;
}